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MikeOxon

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  1. MikeOxon

    Cautionary Tales – 2

    By MikeOxon,


    General
    Last year (October 2021) I wrote a post under this same title in which I referred to the need for caution, when making models based on published drawings. In some cases, even manufacturers’ drawings, especially in the early days, can be suspect, since the finished product was based more on the skills of individual craftsmen, who trusted their practical knowledge over that emerging from the drawing office!
     
    When I designed my recent model of ‘Vulcan’, I derived the dimensions from sketches by the young Swindon apprentice, E.T. Lane. Although these were only sketches, they were made ‘from life’ and I feel are more likely to represent the actual appearance of his subjects than more polished drawings made many decades later.
     

     
    Nevertheless, I was perturbed when I realised that my use of these sketches had resulted in the driving wheels of my model appearing to represent a 7 foot prototype diameter, whereas the RCTS book on GWR Locomotives, Part Two, states that the diameter was 8 feet. This statement has been widely repeated in other works ever since. So, I have spent some time examining the evidence more closely
     
    It is in that subtle matter of ‘appearance’ that Lane’s sketches differ markedly from the works drawing of ‘Aeolus’, a sister engine to ‘Vulcan’, both built by the Vulcan Foundry. The works drawing may well indicate 8 ft diameter wheels but, on looking at the wheelbase relative to the driving wheel diameter on the works drawing, the proportions can be seen to be different from the Lane sketch, in which the driving wheel is noticeably smaller
     
    My first step was to photograph my collection of early broad gauge models together, in order to demonstrate their relative proportions:
     

    My Four recent Broad Gauge Models
     
    It was widely reported that the early engines ordered by Brunel had inadequate steam-raising capacity for main-line performance. Daniel Gooch addressed the problem when he designed his Firefly class, of which ‘Argus’ was a member, One of the reasons I had for constructing my models was to help visualise these differences.  The difference between the sizes of the boiler on 'Vulcan' compared with that of 'Argus' is very apparent when the models are placed together.
     
    ‘Vulcan’ was a sister engine to ‘Aeolus’, both being from the Vulcan Foundry and all the key dimensions are in agreement between my two models.  My earlier model of ‘Aeolus’ was based on a detailed sketch by E.T. Lane, which had copious annotations giving the dimensions of many features of this engine.  ‘Aeolus’ had been re-built with smaller driving wheels when Lane made his sketches but other key dimensions, including the wheelbase, had not been altered, so far as we know.
     
    It appears, however that when Mike Sharman showed a drawing of ‘Vulcan’, derived from an illustration by G.F. Bird in The Locomotive Magazine, 1901, in his book of Broad Gauge engines, published by Oakwood Press, a scale based on the assumption that the driving wheel diameter was 8 feet was added.
     
    When I placed this Bird drawing below the Works drawing of ‘Aeolus’, aligned to the wheelbase, it is clear that the wheel diameters are considerably smaller in the Bird drawing and, indeed, are a good match to the sketch by Lane. 
     

    Drawings Compared (based on wheelbase)
     
    I suggest that 'Vulcan' may have been delivered with 8 ft drivers in 1838 but that these were changed to 7 ft sometime during the 1840s. I note that Lane indicated on his sketch that the leading carrying wheels had 14 spokes, whereas the trailing wheels had only 12. This difference is borne out in the later photograph of 'Vulcan' as a tank engine, although not in the Bird drawing.  Perhaps it is an indication that 'Vulcan' was re-fitted with wheels salvaged from other engines during the 1840s?
     
    There is an early illustration of Ealing Station, dated 1839, which includes 'Vulcan' (or one of the similar engines in the group) apparently in original form with 8 ft diameter driving wheels.
     

    Extract from illustration of Ealing Station 1839
     
    Overall then, another reminder always to treat published drawings with suspicion. Distortion frequently occurs during publication, so that vertical dimensions may not correspond with horizontal ones! There are plenty of traps for the unwary modeller and I hope that not too many have built models of 'Vulcan' to the dimensions shown in the Oakwood Press book.
     
    I am especially pleased, however, to have found that the late Mike Sharman’s own model of 'Vulcan' does appear to have been based on the proportions shown in the Works Drawing, with its larger (8' diameter) driving wheels. A collection of photos of Mike’s models appeared in Railway Modeller, March 1968, so I was able to compare a good side-on photo of his model with the above drawings. 
     
    I should also be interested to know where Mike's tender design came from - I used a 4-wheel Gooch tender with my own model
     
     
  2. MikeOxon

    Christmas Break

    By MikeOxon,


    general
    With the holiday period now upon us, many of North Leigh’s locomotives are now ‘on shed’. In the following photo can be seen my first ‘scratch build’ - a GWR ‘Queen’ class, with a ‘Stella’ 2-4-0 next in line. Disappearing out of view, the back of ‘Lord of the Isles’ can just be glimpsed, while on the front track is a Dean Goods, together with an early PBV.  (The 'back scene' is by Photoshop)
     

    Locomotives ‘On Shed’
     
    Looking back into Broad Gauge days, I remember a comment by Mikkel on my construction method in which I added 3D-printed cladding to a metal boiler – he wrote “Boiler then cladding, like watching a real loco being built”. After some searching, I found an old engraving of the Swindon Boiler Shop, with the boiler of my Gooch Goods being readied for the addition of the cladding

    In the Boiler Shop
     
    In many ways 2020 is a year best forgotten but the lock-down gave me plenty of time to practise using my 3D printer, to make a wide variety of models (both 'Standard' and Broad Gauge). True to form, my Armstrong Standard Goods still needs a number of finishing touches but I think it has captured the ‘look’ of the prototype quite well.
     

    Armstrong Goods
     
    I can only hope that 2021 will see the present restrictions being relaxed, although it will take some time. I also hope to have some more ideas for creating new types of models.  Perhaps I shall also find a few more Amy Wilcote paintings.
     
    My best wishes to those who have followed my posts over the year and for the encouragement you have provided, which is much appreciated
     
    Mike
  3. MikeOxon

    Cleminson to the Rescue

    By MikeOxon,

    I am very grateful to member KH1, who alerted me to the 'Cleminson principle', in reply to my earlier blog entry about 'Milk Churns and Syphons'.
     
    In another thread in the forums, http://www.rmweb.co.uk/community/index.php?/topic/6484-cleminson-chassis-drawing/, I read that there was an article in 'The Engineer' of Feb 15th 1878, describing this system. Back volumes of The Engineer can be downloaded free from http://www.gracesguide.co.uk/The_Engineer_%28Bound_Volumes%29 , so I show an illustration from p111 of the relevant issue.
     

     
    There is a kit available from http://www.brassmasters.co.uk/cleminson_underframe.htm but it didn't quite meet my needs, since I wanted to retain the existing outside frames on my model. I thought it would be fairly easy, however, to build something along similar lines so, having some spare brass sheet handy, I sketched out a design to apply to my K's Low Siphon:
     

     
    I printed this sketch to scale, pasted the parts onto my sheet of brass, drilled the necessary holes for axles and pivots, and then cut out the pieces with jewellers' snips. The hatched areas on the drawings were folded up, to make the axle supports and the tabs within which the centre axle mount slides. The linkage pins were made from unfolded paper clips.
     

     
    The various pieces were then attached to the floor of my Syphon, by means of screws through the pivot points:
     

     
    I had some spare Bachmann wheelsets, so I removed the pin-point ends with a cutting wheel and threaded the axles through my, rather crude, axle mounts. After straightening everything up, I found that the vehicle would now traverse my 15" radius curves successfully! Here is a pic of it running through some pointwork.
     

     
    This was very much a 'quick test' form of construction but, having established that the method works, I think I'll have another go, probably using nickel-silver sheet, which should be much more rigid and able to hold everything in good alignment.
     
    I'm very pleased, as this now opens up the possibility of running the ubiquitous six-wheel coaches on my 19th-century micro-layout
     
    Mike
  4. MikeOxon

    Comparing Armstrong 2-2-2s

    By MikeOxon,


    general
    It's now over two years since I built my first locomotive from scratch, using brass sheet. It's still looking quite good and helped to inspire me to continue with building lots more scratch-built stock. For more information about my model, see 'Railway Modeller', July 2014, "Simply Victorian".
     

    My model of the GWR 'Queen' class
     
    It really was simple to build - basically a brass tube over a brass plate, with a very simple 'chassis' to hold a set of wheels at the right distance apart! As I have commented before, it's really just a wagon that can be pushed along by a motorised tender. I would recommend an early 2-2-2 as a good subject for a first attempt at locomotive scratch-building.
     

    Components of my model
     
    The only real difficulty came as a result of having to make the wheels fit my 'narrow' 00-gauge track, since this meant that I had to make cuts in the sides of the boiler tube so that the wheels could be placed close enough together. That made fitting the splashers, and filling the inevitable gaps, a tricky process.
     
    I've done a lot more reading since then and it is largely fortuitous that my model has a reasonable resemblance to its prototype, as running in the late 19th-century. This came home to me when I started to think about some other engines that have caught my interest.
     
    When I started making earlier types of carriages, I got a lot of information from the report on the accident that occurred just north of Oxford in 1874. That train (a Paddington - Birkenhead express) was headed by two 'Sir Daniel' class engines, which started me thinking about the differences between those engines and my 'Queen' class.
     

    GWR 'Sir Daniel' class
     
    Started in 1866, the 'Sir Daniels' were the first standard-gauge engines to be built at Swindon by Joseph Armstrong, who was faced with the task of overseeing the decline of the broad gauge. On the other hand, the 'Queen / Sir Alexander' class were the last design by Armstrong before his untimely death in 1877.
     
    Both classes remained in service for many years - the last 'Queen' went in 1914, whereas many 'Sir Daniels' had a remarkably extended life, after the rather unusual step of converting them to 0-6-0 goods engines, in which form the last went in 1920!
     
    They were all rebuilt on several occasions, so it is important, when comparing drawings and photographs to consider the period when these were made. By the late 19th-century, photographs indicate that the two classes were looking rather similar so, to bring out the visual differences, I decided to overlay drawings of the two types, as they appeared after re-building by Dean.
     

    Comparison between 'Queen' and 'Sir Daniel'
     
    Both these drawings are shown in Russell's 'Pictorial record of GWR Engines'. I have removed extraneous details and overlaid them, such that the driving wheel centres are aligned.
     
    The front ends of the two classes look very similar, the key difference being that the leading wheels of the 'Sir Daniel' are set 10” further back whereas, at the back, the frames are shorter, with the trailing wheels closer to the drivers. Overall, the 16 foot wheelbase of the 'Sir Daniel' was increased to 17' 6” in the 'Queen' class, the extra length improving stability at high speed. The relative proportions of boiler and firebox also changed, with the Queen having a shorter boiler (by 6”) but a lengthened firebox (increased by 1 foot)
     
    I was quite surprised to see how similar these two engines, with original dates around 10 years apart, had become, after their re-builds. Later, they became even more similar, when the open splashers were filled in and the driving wheel springs on the Sir Daniels were moved below the footplate, like the Queens. Of course, there were numerous detail differences, some of which depended on whether individual engines were re-built at Swindon or Wolverhampton.
     
    In summary, I can see that I could make a model of a 'Sir Daniel' by using exactly the same methods that I used for 'Queen'. At the moment, I feel tempted but concerned that the two would end up looking too similar! If I do tackle a 'Sir Dan', I shall have to choose a prototype with significant differences from my existing model but, if anyone else is thinking of having a go, it should be quite straightforward and I'll be interested to see the result
     

    'Queen' class at North Leigh
     
    Mike
  5. MikeOxon

    Creating a ‘Freak’

    By MikeOxon,


    General
    I completed the draft of this post just before RMWeb went off-line, during its transfer to a new hosting service.  I have made more modelling progress during the last 10 days, so will upload a follow-up article, once I have seen that the current post has settled down in its new home.
     
    Last year, in May 2021, I wrote a post in my blog called ‘From the Stars to Fire Fly’. I drew on contemporary illustrations by E.T. Lane to show some of the engines to which I referred. I now find myself thinking about those engines that came before the ‘Stars’ – usually written off as ‘freaks’ and total failures.
     
    A few of the engines were, indeed, ‘freaks’, since their designers tried ingenious but ill-fated approaches to meeting Brunel’s specification, but most of them were simply too small and too lightly built for reliable service. A selection from ‘The Engineer’, 1910, shows how the outlines of several of these engines compare with ‘North Star’ (top left):
     
    Selection of Early GWR Engines
     
    Although Brunel was a great visionary and created many wonderful engineering works, his knowledge of early railway locomotives was severely limited. At the time when he was planning his ‘Great Western Railway’, locomotive design was still in its infancy. ‘Rocket’ had succeeded at Rainhill in 1829, less than a decade earlier, and it looks as though Brunel had not been following the rapid developments that had happened over those years, Thus, when he drew up specifications for his locomotives, he specified dimensions and weights that were far too conservative. For example, he specified a maximum weight of 10½ tons, already far exceeded by contemporary engines, He also specified a ridiculously low piston speed of 280 feet per minute at 30 miles per hour. This was the sort of speed that might have been used on stationary engines but contemporary locomotives featured speeds of over 500 feet per minute.
     
    The low piston speed required by Brunel implied the use of very large diameter driving wheels – the engine ‘Ajax’ originally had 10’ diameter wheels – which were necessarily very heavy. This left little weight in the budget for the boiler and other components, which were forced to be very small and insubstantial. It was a combination of all these factors – lack of steam raising ability and components that could not take the stresses and strains of regular operation - that made these engines so unsatisfactory and caused great difficulty for his locomotive superintendent, Daniel Gooch, in trying to keep them in working order..
     
    I decided to examine one of these under-sized engines in detail, to learn why they were such failures and, for my first example, I have chosen ‘Aeolus’, one of three ‘large’ engines supplied by Tayleur. According to Brian Arman, in his comprehensive survey of ‘The Broad Gauge Engines of the GWR – Part 1’, ‘Aeolus’ appears to have been the best constructed and, initially, the most reliable. It did not, however, fare very well when entrusted with the first GWR public train on 4th June 1838.  It seems that this engine had difficulty in maintaining a speed of 6 mph with a loaded train.
     
    As originally built, ‘Aeolus’ had 8’ diameter driving wheels, with a very small firebox and boiler. We are fortunate to have a copy of a works drawing of the engine, as built:
     

    Aeolus Works Drawing
     
    The very small diameter of the boiler is vividly displayed in the above drawing and, out of interest, I overlaid the head-on view from this drawing with a drawing of ‘North Star’ to the same scale. The difference is dramatic!
     

    Aeolus and North Star Boiler Comparison
     
    Despite its initial poor performance, Gooch took ‘Aeolus’ in hand and it was later accredited with some fast runs with very light trains but it was soon laid aside, before becoming one of the first engines to be re-built at the new Swindon Works in 1843.
     
    Once again, I must pay tribute to that young pupil at Swindon, E.T. Lane, who sketched many of those early engines, which he saw as he walked around the works. Some of his sketches were worked up into detailed drawings but I find that it is often the sketches that reveal much more character. Sadly, Lane died at the age of 20; a reminder that life in the early 19th century was far more precarious than most of us experience nowadays.
     
    His sketches of Aeolus, made during or shortly after its re-building at Swindon. show that the driving wheels were reduced to 6’ diameter and the proportions of both boiler and firebox were altered, to allow for a much larger firebox. Other details remain unchanged from the original works drawing. Lane’s sketches are annotated with dimensions of the various parts, which I have used as the basis for a 3D model.
     
    First Steps towards a 3D Model
     
    Lane’s sketches were probably made in a notebook as he stood with the engine in front of him. They are far from being accurate drawings but capture the ‘character’ of the engine very well. The value of these sketches lies in the copious annotations of dimensions, which I assume he must have measured himself from the actual engines.
     
    My challenge was to use the combination of the overall appearance and the detailed dimensions to create a drawing from which I could make a 3D model. For this, I started by using my usual method of importing the Lane sketch into ‘Fusion 360’ as a ‘canvas’. I then calibrated the canvas so that the overall length of the engine, as annotated by Lane, corresponded to the dimension of a 4 mm scale model.
     
    Outside Frames
     
    The first part of the engine that I addressed was the right-hand outside frame. I started by drawing a rectangle corresponding to the annotated dimensions of the frame, then adding the wheel mountings, as shown in the screen-shot below:
     

    My dimensioned outline of the Frames in 'Fusion 360'
     
    Once I had the main outlines of the frames correctly scaled and positioned, relative to the defined wheelbase and wheel diameters, I could use the ‘push/pull’ tool in 'Fusion 360' to create 3D ‘bodies’ of the frame and splashers (rivet detail and springs will be added later.), as shown below:
     

    My 3D Model of Frame and Splasher Fronts for ‘Aeolus’
     
    Firebox-Boiler-Smokebox
     
    The information on these parts is even more limited, as Lane’s sketches only show the side elevation. We know that the boiler retained its original 3’ 6” diameter and, when rebuilt, had a length of 7’ 11”. The cylinders, after rebuilding, measured 15” bore by 18” stroke.
     
    The end-view in the Works drawing shown above, gave me the relative positions of boiler and cylinders. I used this information to extrude the smokebox from the Works drawing, as shown below. The depth of the smokebox is given by Lane as 2’ 2”.
     

    Extruding the Smokebox in 'Fusion 360'
     
    The locations of the cylinders are determined by the positions of the cranks on the driving axle. Because these are widely spaced. It is necessary to increase the width of the smokebox to accommodate them. I took guidance from a photograph of the sister engine ‘Vulcan’, which shows the sides to have been ‘bulged’ out from a point close to the mid-height of the boiler.
     

    ‘Vulcan’ – rebuilt as a tank engine 1858
     
    I extruded the firebox, similarly to the smokebox, to a length of 12 mm. My model boiler is simply a tube, 31.67 mm long. of 14 mm inside diameter and wall thickness 0.75 mm, to represent the cladding.
     
    Boiler Fittings
     
    The design of the boiler fittings – dome, inspection cover, and chimney – followed my usual methods of using a combination of the ‘push/pull’ and the ‘rotate’ tools in 'Fusion 360', to create these cylindrical structures.
     
    The inspection cover and a plinth for the combined dome and safety-valve cover were joined to the relevant main components, with the ‘chamfer’ tool being used to create a smooth transition at the join. I created the rather complex outline of the upper part of the safety-valve cover from a cross-section sketch, using the ‘rotate’ tool to convert this sketch into a solid body.
     
    The drawing by G.F.Bird, produced early in the 20th century for ‘The Engineer’, shows fluting around the periphery of the dome. I was not sure about this, as it is not visible on the photo of ‘Vulcan’. I decided, however, that some short lines on the contemporary Lane sketch were probably intended to indicate fluting, so decided to add this feature. I created a single slot in the centre segment of the dome and then used the ‘circular pattern’ command to repeat the feature all around the periphery, as shown below:
     

    Creating the fluted dome segment in Fusion 360
     
    After adding the fluting, the complete dome and safety valve cover appeared as shown below:
     

    My 3D-model of the combined Dome and Safety Valve Cover
     
    In contrast, the chimney was straightforward but, from the Lane sketches, it appears to have been fitted over a separate plate at the top of the smokebox. I created this plate first, as a wrapper over the smokebox, and then produced the chimney itself by using the ‘rotate’ tool from a cross-section drawing. Finally, I created a fillet at the joint between these two parts, as shown below:
     

    Creating the Chimney and its Plinth.
     
    Now I had all the parts needed to put together the main body of the engine in ‘Fusion 360’. I have not yet added details such as rivets, boiler bands, etc. but the main outlines are clear. Because of the small diameter of the boiler, there is a lot of ‘open space’ between the frames, which will need filling with a representation of the motion!
     

    Assembly of the major components in Fusion 360
     
    Next steps
     
    I now need to pay attention to the chassis. From the sketches by Lane, it is surprising to see that this engine retained its primitive ‘loose eccentric’ valve gear, even after re-building in 1843. The layout of this gear includes the use of a ‘weigh-bar’ in front of the smokebox, which looks very similar to that which Stephenson had used on his ‘Planet’ locomotive, designed back in 1830.
     
    Since I only have a side elevation view plus sketches of a few details by Lane, I shall have to spend some time considering the probable layout of the visible components in front of the smokebox. This will be the main subject of my next post.
     
    Mike
  6. MikeOxon

    Creating a Pantechnicon

    By MikeOxon,


    General
    Even after a long career in research, I am still frequently surprised by the new information that emerges from small beginnings!
     
    After completing my Britzka model, I placed it on my BG carriage truck model for some photos. The Britzka was rather a tight fit between the truck rails, so I went back to Eddy’s Data Sheets from the Broad Gauge Society (BGS) to check the dimensions. It turned out that it is my carriage at fault and I shall revise my model to make it a little narrower (easy to do with a 3D printed design!). As I was looking at the BGS data sheets, however, I noticed that there was a very similar truck described as a 'Road Van Truck' (Data Sheet 105B).  I started to investigate further and so started a new line of research ...
     
    From the BGS data sheet, the ‘Road Van Truck’ looks similar to the carriage truck I have already modelled, except for a longer body and slightly increased wheelbase: body length increased from 15’ 4” to 18’ 6” and wheelbase from 8’ 6” to 9’ 0”. It was a straightforward task to increase these dimensions in my 3D model of the carriage truck, without having to re-design any of the components:
     

    3D-model of Road Van Truck – revised from Carriage Truck
     
    In describing this truck, Data Sheet 105B includes the information that “… of general interest are the notes in BGS Journal [Broadsheet] No.26, p10, which refer to the first recorded use of a Furniture Van Truck with Pantechnicon, 1847, transported by rail.”  Fortunately I have the complete set of digitised ‘Broadsheet’ issues, which are available from the Broad Gauge Society, so I could look up the article entitled 'Knee Brothers of Bristol'
     
    Knee Brothers, Bristol
     
    ‘Broadsheet’ No.26 contains an article about the firm of Knee Brothers, a removals firm in Bristol founded in 1839.  According to this article “In 1844 William Knee had a special mammoth heavy version of a horse drawn spring furniture van built to his own specifications at a wheelwrights in the St. Pauls district of Bristol. The felloes of its wheels were recorded as being 9" wide. This was the first pantechnicon to travel by rail.”   The first record of such rail transport was in 1847, when the furniture of a contractor for the construction of the Bristol and Exeter Railway was conveyed on the B&ER, using GWR rolling stock. There is an early advertisement by Knee brothers, which shows the Pantechnicon mounted on a GWR Road Van Truck, as shown below:
     
     

    Contemporary Illustration from Knee Brothers Advertisement
     
    According to the ‘Broadsheet’ article: “The Knee Brothers 'pantechnicon' had wagon sides and strouters (wooden supports to strengthen wagon sides) of blue-grey, similar to warship grey, with brown (possibly varnished wood(?) shafts and axles.  Springs were black whilst the wheels were red (similar to wheels of later G.W.R. horse drawn road vehicles). Its tarpaulin(?) covering was dark charcoal grey with side and front owner signs of cream background with black sign writing. An italic "No. 1" was inscribed on the wagon side just inside the front strouter.  Strouters on this vehicle sides, from just behind the region over the front wheels (i.e. about two-thirds along the wagon side from its rear), were slightly tilted from the true vertical towards the vehicle front for remaining length of the wagon side, whereas the other strouters appeared to be truly vertical.  This practice seemed to have been commonplace with techniques of road wagon construction in the nineteenth century.”
     
    It is also states that “The Great Western Railway broad gauge van truck on which the 'pantechnicon' was pictured was in all chocolate brown livery except for its wheels and springs which were black. Lettering "G.W.R. No. 66" was also in black” This description does not conform with other GWR livery references, which state that all parts of goods vehicles were brown, including wheels and undergear. The lettering was probably incised into the solebars, as described in Great Western Way (1st.ed).  Whether it was coloured black seems questionable
     
    Creating a Model
     
    Apart from there being no dimensions, this description and illustration above seemed adequate for me to attempt making a model. The length of the Road Van Truck has been given as 18’ 6” and, in the above illustration, the ends of the pantechnicon are around one foot from the ends of the truck, so I have guesstimated the length of the pantechnicon as 16’ 6”. I used the perspective tools in Photoshop to ‘square up’ the side of the body to estimate other dimensions on this basis. I have described this method in more detail in an earlier post.
     
     

    Estimating dimensions after perspective adjustment in Photoshop
     
    I also had to estimate the width of the body and decided, somewhat arbitrarily, to make the width across the panelled sides 4’9”, widening to 6’ 0” above the large rear wheels. This allowed sufficient clearance for wheels with 9” felloes (i.e. rim width) to fit within the side-rails of the Road Van Truck.
     
    Using ‘Fusion 360’ modelling software, I extruded the van body from a rectangle measuring 66 mm x 19 mm to a height of 14 mm. I then extruded the upper part of the sides to an overall width of 24 mm. I used the ‘Shell’ tool to hollow out the interior of the vehicle to leave an outer wall width of 1 mm.
     
    For the side panelling, I drew a pair of rectangles of appropriate size, one above the other near the rear end of the side. I then used the ‘Pattern’ tool to create an array of two rows of 19 panels along the length of each side. I see this ability to create repetitive features like these panels as a great advantage of 3D modelling over other construction methods.  In accordance with the description given above, I modified the front six panels so that the uprights between the panels were inclined at 5 degrees from vertical.  At this point, the 3D extruded body appeared as shown below:
     

    My first-stage extrusion of Pantechnicon body
     
    My next step was to add the front board above the body and a series of hoops to the same profile along the length, to the tail-board. Then I designed the curved strouters, which help to support the overhanging part of the upper sides. I also created wheels of 9” width and placed them in appropriate positions, so that I could check the clearances within my Road Van Truck.  The hoops were created as individual bodies, so that they can be printed separately, lying flat on the printer bed.  The ‘test assembly’ of these various parts within ‘Fusion 360’ is shown below:
     
     

    Test fit of my pantechnicon body on road van truck
     
    Designing the Chassis
     
    It’s not possible to glean much about the chassis from the available illustration but there appear to be separate under-frames for the front and rear axles, providing mounts for semi-elliptic springs above the axles.
     
    The front underframe is fitted to a swivel mount below the floor of the vehicle body and also carries attachments for two pairs of shafts, to attach the horses. In the illustration, these shafts are shown swung upwards against the front board of the vehicle. There is no indication of a drivers seat, although this would have been placed near the top of the front board.  By drawing on my experience from designing the Britzka carriage, I sketched out an underframe comprising a rectangular frame to carry the springs for the rear axle. From this, two longerons reach forward to carry the fixed ‘fifth wheel ‘, which provides a bearing for the pivoting fore-carriage.  The fore-carriage is a separate component carrying the frame for the springs over the front pivoting axle, plus mountings for the shafts, for two horses.
     
     

    My design for the pantechnicon chassis
     
    For the shafts, I turned to Janet Russell’s book: “GWR Horse Power”, which contains dimensioned drawings of various types.  I used one of her drawings as a ‘canvas’ in ‘Fusion 360’, from which I extruded two sets of shafts to attach to the front of my chassis.. I arranged these shafts to fit onto a cross-shaft, so that they could be raised against the front panel of the body, as shown in the illustration above, or lowered for attachment to a pair of horses. Once I had brought all the parts together in ‘Fusion 360’, the 3D design looked as below:
     
     

    My 3D design of the complete Pantechnicon undergear
     
    I could now place the body over the chassis in ‘Fusion 360’, to assess the overall assembly before printing the various components.
     
    Printing
     
    As usual, after all the design effort, the printing came as something of an anti-climax. Once again, I was pleasantly surprised by how cleanly my printer produced even the smallest and most delicate parts. I laid them all out for a photo, just as I took them from the printer bed (although one hoop somehow disappeared to the carpet monster and I had to reprint a second set)
     

     
     
    For the record, the print times (estimated by the Cura software) were:
     
    body 67 min wheels (set of four) 20 min underframe 10 min fore carriage 7 min front board 7 min axles (pair) 5 min hoops (set of four) 4 min shafts 3 min  
    The assembly was very straightforward. Only the front board, hoops, and axles needed to be fixed into place I fixed a ‘perch pin’ into the centre of the ‘fifth wheel’ underneath the body and the fore-carriage was then slid onto this pin. Similarly, the wheels and shafts were slid onto lengths of 0,7 mm wire, which provided the pivot points.
     
    I painted the body light grey, as described in the ‘Broadsheet’ article, while the axles and shafts are brown, and the wheel faces red.
     
    I produced the lettering using ‘Cooper Std’ and ‘Garamond’ fonts, which are reasonably good matches to the prototype illustration, shown below.
     
     

    My layout of the front panel text
     
    After laying out the text and the Bristol coat of arms in Photoshop, I printed the front and side panels on ink-jet printable self-adhesive vinyl, which I stuck onto the 3D-printed model.  The end result, without a tilt cover, is shown below:
     
     

    My model pantechnicon (less tilt cover)
     
     

    Rear View, showing Tailgate
     
    Canvas Tilt Cover
     
    For the cover, I first wrapped the body of the van in cling film, stretched over the hoops and shaped by hand. I then wrapped a length of wet plaster bandage over the cling film and smoothed it down into place. Once I was content with the general appearance, I placed the model over a radiator to dry.
     
     
     
    My model wrapped in cling film and plaster bandage
     
    Once the plaster had dried, I applied a rather thick layer of black acrylic paint over the bandage, working it into the texture of the surface to make as opaque a coating as possible. Once this had dried, I trimmed off the excess plaster, below the top of the body and took the portrait below:
     
     

    My model with Tilt Cover added.
     
    As I indicated at the outset, the thought of building a pantechnicon was not in my mind until I followed the train of thought that started from the BGS Data Sheets!  It has proved to be an interesting model to create and I think the use of 3D printing provided a simpler course than ‘traditional’ modelling methods. All the parts were extruded from 2D drawings so, if you can create a drawing for a ‘Silhouette’ cutter, it can be turned into a 3D model! In fact, some of my first 3D-printed models were created in this way from drawings that I had previously used for Silhouette-cut carriage sides.
     
    I notice that there is an earlier thread on this site about modelling a 4 mm scale pantechnicon from a kit. I suspect that it was the ‘Gem’ kit, which is no longer available.
     
    Mike
     
  7. MikeOxon
    It’s a while since I’ve posted anything here and this entry is more in the nature of a ‘placeholder’ than a description of actual progress. It is hard to believe that it’s almost three years since I started building my model of GWR No.184, which was the (standard gauge) locomotive that started my interest in earlier locomotive designs.
     
    That model was a fairly simple build, although I did manage to make some basic errors, largely by failing to understand the compromises needed, when designing for the non-prototypical 00 gauge. As a result of these errors, my original model, while looking very attractive, would not run smoothly, because the outside cranks had insufficient clearance from my over-wide outside frames. Because the model looked nice, I was reluctant to pull it all to pieces and start again.
     
    Then I started looking at Broad Gauge models and realised that the standards adopted for these models are usually much finer than those I had been used to, when modelling in 00 gauge. Whereas I had previously been pleased to produce a good ‘impression’ of the prototype, I felt that I should strive for higher standards in my ‘new’ gauge.
     
    As described in previous entries, I managed to overcome the difficulties in building a mail coach, in a condition appropriate for the 1860s, and then started looking at an appropriate locomotive for a mail train. I already have a ‘Rover’ class ‘single’ built from a K’s ‘Milestones’ kit, which has allowed me to built a small diorama, including the mail coach.
     

     
    My aim, however, was to construct a ‘Waverley’ class 4-4-0, by using the Broad Gauge Society (BGS) kit of a Gooch Standard Goods to provide the boiler. The BGS kit presented some difficulties but I eventually succeeded in completing the boiler assembly and also constructed a pair of inside ‘sandwich’ frames.
     
    It was not difficult to produce a similar set of inside frames for the 4-4-0 and so generate a basic framework for the new locomotive.
     

     
    It than became apparent that further progress was going to be more difficult than I had anticipated and, as a result, I have been pondering various possibilities.
     
    The exposed driving wheels, with their bicycle-like splashers, are such a large part of the ‘character’ of these locomotives that I feel it is essential to achieve a good representation of these features. I suspect that it will be very difficult to cut out suitable shapes, by hand, in thin brass sheet, without introducing distortions that will spoil the overall effect. In another thread in these forums, however, I read a discussion of electrolytic etching, which seems to offer a potentially useful technique for making those rather demanding outside splashers. This method will, however, require a lot of experimentation, before I shall be able to produce suitable components.
     
    I am still unsure, however, whether this will result in a strong enough structure to provide both a good appearance and appropriate clearance around the wheels, to achieve smooth running. My current thought is to cut out some components in plasticard, by using my Silhouette cutter. If only the cutter could work on brass sheet!
     
    My other thought is to provide a separate internal chassis to hold the running gear in a sort of ‘bogie’, which will make my current, rather lightweight frames purely ‘cosmetic’. This would mean building a small chassis, very similar to that which I built for No.184, and mounting it underneath the firebox of the existing boiler. An advantage, arising from this, would be that I could suspend the resulting ‘bogie’, to provide some flexibility in the wheelbase of this rather long 4-4-0.
     
    My last concern is whether I’ll be able to obtain wheels that will adequately capture the appearance of the real locomotive. There seems to be no commercial source of 4mm scale, 24-spoke 7-foot driving wheels so, again, I shall probably have to make a compromise. Otherwise, I’ve been contemplating whether I could possibly build my own spokes inside a commercial 28mm diameter rim.
     
    So, my current problem is that of seeing many difficulties and not yet being sure of how best to overcome them. It may take some time but my experience is that, eventually, a solution will become clear.
     
    In fact, this has recently happened in the case of No.184, where I realised that I could cut away the existing outside frames, without damaging the rest of the model. I then used some short lengths of BGS bridge rail, to strengthen the remaining part of the chassis and to provide attachment points for new outside frames, at a narrower spacing.
     

     
    This has given me the free-running that is needed, so that it is worth continuing to add a motor and gearbox, to complete that model
  8. MikeOxon

    Diagram U29 Revisited

    By MikeOxon,

    I write two blogs, one on pre-Grouping GWR and one on Broad Gauge GWR but, while I am experimenting with 3D printing, I shall be hopping between the two so, if you wish to follow my various trials, it’s necessary to look at both.
     
    From 2D to 3D modelling
     
    It’s almost six years since my modelling aspirations took a great leap forward, through my acquisition of a ‘Silhouette Portrait’ cutter.  The first prototype that I chose to model with my cutter was the Tri-composite carriage, built in 1886 to diagram U29.  This carriage presented quite a challenge in preparing the 2D drawings!  In fact, I commented at the time that “It turned out that Diagram U29 is somewhat 'the design from hell', since every panel seems to be unique! It certainly gave me plenty of practice in using the drawing tools.”
     
    I enjoyed making the Tri-composite model and a number of other models from a similar period but there were some aspects of my constructions that I never felt were really satisfactory, especially my fabricated clerestory roofs.
     
    Now that I’m exploring the possibilities of 3D printing as a modelling tool, I thought it would be interesting to re-visit the panelled carriages from the late 19th century and see if I could now produce something better.
     
    After creating a few relatively simple 3D models of carriages from earlier Broad Gauge times (described in my other blog), I decided that it was time to move on and tackle something a little more complex.  I felt that I had gained a reasonably firm toe-hold in Fusion 360 drawing techniques, so a panelled coach seemed a reasonable next step.  I also thought that 3D modelling offered the potential to create a clerestory roof rather more easily than the fabrication techniques I had used earlier.
     
    Since I already had my 2D drawings of diagram U29 ( prepared in Autosketch and saved as DXF files) I could use these to create the various panels and mouldings by use of the push-pull tools in Fusion 360.  The first stage was to prepare the carriage body and I decided that, rather than add raised mouldings, I preferred to ‘emboss’ the panels into the outside walls.
     
    My 3D Modelling Process
     
    As described in an earlier post, I started from one end of the carriage, drew the end-wall profile and then extruded this profile to the length of the carriage.  I used my 2D drawing, pasted onto the end wall, to emboss the panels by 0.5mm from the outside framing.  From previous experience, this depth is around the minimum that will show clearly when using my printer.
     
    One caveat is that all shapes to be extruded must be ‘closed’  I found that one of my panels had a tiny gap in one side that only became visible on very close inspection.  It had me stuck for some time, as I tried to determine why that particular panel refused to cooperate!  What’s good enough for the Silhouette cutter will not do for the more demanding task of 3D construction.
     
    I also realised that there were several different depths to which different features of my model needed to be recessed.  These include the panels, the various window sections, and the window openings themselves.  In each case, the part of the drawing to be extruded must be placed on the appropriate plane of the model for the ‘push-pull’ tool to work.  My method was to make the shallowest panel sections first, then shift the ‘sketch plane’ to this deeper location, to select the next areas (e.g. window frames) for further depression, and so on.
     
    To save having to work on the two sides separately, I completed all the detailing on one side then ‘split’ the model lengthways and created a mirror image for the other side, as described in a previous post.
     
    Some of the key stages in constructing my model are shown in the following screen shots from the Fusion 360 software.  In fact, having struggled at times to find my way through the various modelling procedures, I went back through the steps, taking these screen-grabs as I went, and found it a lot easier the second time!


    Stages in 3D Modelling diagram U29
     
    The roof required separate consideration, since I did not want a solid model but had, nevertheless, to provide support for the roof panels.  I decided to split the model horizontally at eaves level and treat the carriage body and roof independently, as regards interior fittings, with the intention to join the parts together again for final assembly.
     
    Once the roof had been removed,  I drew a rectangle on the top of the sold carriage body and extruded downwards, to open out the interior of the carriage, leaving a 1mm thickness floor at the base.  I then drew rectangles for the bases of the partitions and seats, and ‘pulled’ these upwards to their appropriate height within the carriage body. (all these procedures are described in more detail in a previous post)
     
    For the roof, I left the flat base in place, to support the side sections and used the ‘push-pull’ tool to open out the interior of the clerestory section.  I used my existing 2D drawings to place the panels and window openings on both sides of the clerestory.  To ensure adequate support for the clerestory roof, I allowed the ‘Cura’ slicer software to generate supporting in-fill within the raised section, which I planned to remove after the model was printed.
     
    Once I had drawn these two components in Fusion 360, I exported the data to the Cura slicer program, to prepare for printing.  Although the overall dimensions lay within the specified print volume (130x130x130mm) of my Geeetech E180 printer, the Cura software would not accept the model until I rotated it diagonally on the print bed.  The screen display of the two components, when prepared for printing are shown below:
     

    Screen Views of Model Ready for Printing
     
    Printing the Clerestory Roof
     
    Because of its shorter printing time, I decided to print the clerestory roof first.  I was very pleased with the outcome and felt that the surface finish, after being printed on the diagonal, seemed smoother than when I had printed items aligned along the X-axis.
     
    The space inside the clerestory was filled with a ‘grid-style’ supporting structure for the top surface and, at first, I was a little apprehensive about how easy this infill would be to remove.
     

    Clerestory in-fill During Printing

    Once printing had completed, the underside of the roof did look rather daunting but, in practice, the in-fill was not really difficult to remove.  The support structure is much weaker than the main structure and I found there was little possibility of damaging the main structure while attacking the in-fill.  
    The first stage was to insert a knife into the slots around the edges of the infill.  Then it’s a case of chiselling away at the material until the cavity has been cleared.  After initial trepidation, I found I could proceed quite rapidly, scraping away all the debris!
     

    Stages in Scraping Out the In-Fill

    Printing the Carriage Body
     
    While I was engaged in all this scraping and cleaning-up, my 3D Printer was busily getting on with the carriage body.  This is an advantage of 3D printing - it does not stop the modeller from getting on with other things!   The carriage body took over 5 hours to print, so I had plenty of time not only for modelling but also to take my cycling exercise.
     
    Unlike the roof, the body needed very little by way of cleaning-up, apart from opening out all the window openings.  I was pleased that most of my design objectives were achieved in this ‘first go’.
     

    Printed Carriage Body after Clearing Window Apertures

    Assembling the Components
     
    There’s quite a lot of ‘fettling’ still to be done but I finish this post with a photo of the assembly after placing the roof over the body.
     

    3D Printed Tri-Composite Carriage to Diagram U29
     
    The result is a much more robust body than I had made from Silhouette-cut plasticard.  With 3D printing, I don’t have the advantage of pre-printed body sides, which I could produce with the Silhouette cutter.  One thought is to investigate combining both techniques, with 3D printing for the main structure and Silhouette-printed laminates to provide elaborate pre-Grouping liveries.
     
    More ideas to try
     
    Mike
  9. MikeOxon

    Early GWR 'Absorbed' Engines

    By MikeOxon,


    general
    I wrote a Forum post about some of these ‘absorbed’ engines back in 2014 but it has now been archived and has lost its illustrations, so I thought it was worth restoring these in this blog post, which is partly based on my original text.
     
    Some time ago, I acquired a bound set of the RCTS "Locomotives of the Great Western Railway", mainly to learn more about the various pre-grouping designs by William Dean.  I had tended to skip over the volumes on 'Absorbed Engines' but later found myself browsing Volume 3 and realising what a strange and wonderful collection of engines made up the first standard-gauge locomotives to run on the GWR. These booklets are now available again on a print-to-order basis or in digital form.
     
    Of course, the early GWR was a Broad Gauge railway and it was only in 1854, during the drive Northwards, that it came to own any standard-gauge locomotives at all.  The first batches of these were acquired from the Shrewsbury & Chester and Shrewsbury & Birmingham Railways.  What an extraordinary mix of types these were, quite unlike anything we usually associate with the later GWR.  
     

    Shrewsbury & Chester Rly. as GWR No.14

    Some were Bury-type locomotives, with bar frames, others were 'long-boiler' types, with a gothic firebox hung behind all the wheels, and there was even an 0-4-0 with an intermediate drive shaft (built by the Vulcan Foundry).  At that time, there was a brief vogue for intermediate drive shafts, since these decoupled the valve gear from both vertical movements of the springs and lateral thrusts from the flanges on the driving wheels.
     

    Shrewsbury & Chester Rly. - GWR No.34
     
    This 0-4-0 was one of two that became GWR Nos. 34 and 35.  They were delivered in 1853 and both were withdrawn in December 1865. 
     
    Another former Shrewsbury & Chester engine that later gained notoriety was the long-boiler 2-4-0 GWR no.5, built by Longridge & Co., which was involved in a fatal accident at Rednal on 7th June 1865.
     

    Shrewsbury & Chester Rly. - GWR No.5
     
    A little later than this first group were the former West Midland Railway engines, which were added to the GWR fleet in 1863. This amalgamation brought in some of the old stock from the Oxford, Worcester & Wolverhampton Railway (frequently referred to as the 'Old Worse & Worse').  The only known illustrations of most of these early locomotives are drawings by E.L.Ahrons, a great chronicler of early locomotive history.  One of his drawings shows an ex-OW&W engine that would, perhaps, have seemed more at home in the Wild West than the West Midlands:
     

    OW&W Rly – as GWR 223
     
    There were two of these engines, one carrying the name 'Ben Jonson', and they worked branches in the Chipping Norton area until 1877, the other becoming known colloquially as "Mrs Jonson".  Note the outside steam pipes to the cylinders and the (somewhat squashed) safety valve cover.

    Another West Midland engine, which is better known because its photo appears in 'Great Western Way', had the unusual feature of outside Stephenson valve gear.  It became GWR No.219, from a class of six, originally built by the Vulcan Foundry for the Shrewsbury & Hereford Railway in 1853/54. 
     

    Shrewsbury & Hereford Rly. - as GWR 219
     
    I found that there are extensive records of all the locomotives built by the Vulcan foundry on the web. These records includes lists of locomotives deliveries by years, in which the S&H engines appear as below:



    There is also a drawing of one of these engines in ‘The Engineer’, showing both the locomotive and its tender, which gives a better sense of its proportions than the oblique photograph.
     

    Shrewsbury & Hereford Railway – as GWR No.215

    According to Ahrons, one of these engines could still be seen "lying in a heap of scrap behind Swindon Works in 1886".  

    Some of these early engines survived well into the 20th century, usually after having been re-built several times.  The last engine from the OW&W. 0-6-0 No.58, seems to have been around until 1921, by which time, after several re-buildings, it had acquired a conventional GWR appearance as GWR No.47.
     

    OW&W Rly. Re-built as GWR No.47
     
    After my initial look at thee ‘absorbed’ engines, I came across an article entitled "Some Early Great Western Recollections" by C.M.Doncaster in the April 1942 "Railways" magazine.

    The author photographed engines in the late 19th century at Reading Station, as a member of his school's photographic society, and recalls that he casually snapped No.184, never dreaming that this engine dated back to 1853, when it was supplied to the OW&W by E.B.Wilson and Co.  He wrote that, in 1895, it was not unusual to see these engines drawing trains of ten 6-wheel coaches   He even made a simple water colour of such a train, since, most unfortunately, he wrote that his photograph was not fit to reproduce.

    This article led me to explore these engines in more detail.  Six were supplied to the OW&W in 1853; they were 2-4-0 engines, somewhat similar to the 'Jenny Lind' 2-2-2 design produced by the same company.  As it happens, No.184 was not camera-shy and appears in two photographs in the RCTS survey of GWR Locomotives (Part Three): one as re-built at Wolverhampton Works in 1877 and another, after a further re-build in 1893. This particular engine was finally withdrawn in late 1899 and the whole class had gone by 1904.
     

    OW&W Rly. - rebuilt as GWR No.184

    I have looked into some of the background to both this locomotive and the Oxford, Worcester & Wolverhampton Railway, in general. so share this information, in case it is of interest to other modellers.

    The OW&W was initially planned as a mixed-gauge line, with Brunel as chief engineer.  Apparently, Brunel grossly under-estimated the costs and the money ran out in June 1849.  After a lot of wrangling, the line was eventually completed as standard-gauge only.

    David Joy (best known as the designer of the 'Jenny Lind' and of his radial valve gear) was appointed locomotive superintendent in 1852 and his diary (see https://steamindex.com/library/joydiary.htm ) gives some idea of the precarious state of the railway at that time.  He writes that when he arrived, the line was due to open in a fortnight's time, on May 1st, and he had to scour the country to get some locomotives for working the railway.   He scraped together a miscellaneous collection for the opening day, including a four-coupled " Jenny" (known as engine 'A') from the Railway Foundry in Leeds, with the cheque (£1,250) in his pocket to pay for it!  Remarkably, this ‘second hand’ engine survived into GWR ownership as No.206 and was finally withdrawn in 1876.
     

    David Joy’s engine ‘A’ – later GWR No.206
     
    Fortunately, after a few months working with these second-hand machines, relief came with the arrival of the first new locomotives, built by Hawthorns in 1852, and six more by the Railway Foundry (then recently re-named E.B.Wilson & Co.) arrived in 1853, starting with No.21.  It was these latter engines that later became the GWR '182-class' and they were clearly David Joy's favourites.  He wrote "This 21 class would always answer to any little nursing, and would go"  For example he: "received an order for an engine, two first-class carriages, and a van, and a driver who dare run........ We were at Yarnton or Wolvercot Junction on the morning, and all ready to take our passengers from the Great Western Railway special. I was, of course, on the engine — No. 21."  A report was sent from one of the stations that the "special train had passed at 60 miles an hour." , This report, in due course, came before Joy, who remarks " I countersigned it, ' Yes, all right.' ".  There are plenty of other fascinating insights into the running of these early engines in the diaries, including several accidents, which Joy described as 'spills'.


    OW&W Rly. No.21 (From David Joy’s diary)

    In 1860, the OW&W amalgamated with the Newport, Abergavenny and Hereford Railway and the Worcester and Hereford Railway, to become the West Midland Railway, which, in turn, was amalgamated into the GWR in 1863
     

    OW&W No.21 (later GWR 182)

    All this colourful history convinced me that one of these engines would be an excellent subject for a model.  I found that No.23, re-built as GWR No. 184,  survived until October 1899, still working trains in the Oxford area.
    The construction of my model is described in a series of posts, starting with   https://www.rmweb.co.uk/blogs/entry/14895-another-new-old-engine-1/


    My model of GWR No.184 with motorised tender (in Wolverhampton livery)

    List of OW&W Locomotives

    nos. 1 - 20     12 Passenger 2-4-0 and 8 Goods 0-6-0,  built by Hawthorn in 1852/3
            became GWR 171 – 181 (Pass - with some exceptions) and 239, 241 – 243/5/7 (Goods)

    nos. 21 - 26    6 Passenger 2-4-0 built by E B Wilson in 1853
            became GWR 182 – 187

    nos.  27 - 30/ 34    5 Goods 0-6-0 built by E B Wilson 1854/5
            became GWR 248 – 252

    no. 31        Engine 'A'  2-4-0, built by E B Wilson in 1849, bought second-hand 1852
            converted to 2-2-2 in 1855,
            became GWR 206

    nos. 32, 33    'Ballast' engines 0-6-0, built by E B Wilson 1854/5
            became GWR 278 & 279

    nos  35, 36    small 0-4-2ST, built E B Wilson 1853
            became GWR 221 & 222

    nos  37 - 39    3 Goods 0-6-0, designed Peacock,  bought from MS&LR 1854
            one (38) sold, others became GWR 237 & 238

    nos. 40, 41    2 Passenger 2-4-0,built by E B Wilson 1855
            became GWR 188 & 189

    nos. 42, 51    2 Passenger 2-2-2, built by E B Wilson 1856 (large 'Jenny Lind' type)
            became GWR 207 & 208 (51 named 'Will Shakspere' sic)

    nos. 43 - 46    4 Goods 0-6-0,built by E B Wilson 1856
            became GWR 264 – 267 (264 rebuilt as no.49)

    nos. 47 - 50    4 Goods 0-6-0T, built by E B Wilson 1856
            became GWR 231 – 234

    nos. 52, 53    2 Passenger 2-2-2T, built by R Stephenson 1859
            became GWR 223 & 224 (52 named 'Ben Jonson')

    nos. 54, 55    2 Goods 0-6-0,built by Kirtley, bought from MR 1860
            became GWR 280 & 281

    nos. 56 - 59    4 Goods 0-6-0, two built by Kitson and two by R Stephenson 1860
    became GWR 294 – 297 (294 rebuilt as no.47)

    Examples of each of these types are illustrated in RCTS 'The Locomotives of the GWR - Part Three'

     
  10. MikeOxon
    Since my previous entry, I've been spending some time thinking about possible coaches to model for my North Leigh branch. I have found that information rapidly becomes much more sparse, as one delves earlier into the Victorian period
     
    There's an additional twist, in the case of GWR coaches, in that the early GWR was a broad gauge railway and the earliest narrow (i.e. standard) gauge stock only came into the company as a result of acquisitions. There was a long, depressed period, when the company was in financial difficulty and the writing was clearly on the wall regarding the broad gauge. Very little new stock was built for many years until, eventually, a new carriage works was built at Swindon in 1868 The Lot system for carriages and wagons had been introduced in 1867 and was now revised for the new, more sophisticated designs, starting with Lot 57 for 15 standard gauge six-wheel carriages, finished in May 1872. After that date, the progress of the designs has been well-documented
     
    Before the 1870s, most railway coaches had been built by specialist builders and many of the coaches that were acquired by the GWR had been built originally by the firm of Joseph Wright and Sons, Saltley Works, Birmingham.
     
    I've been doing a little 'armchair research' into this earlier period, with the help of books such as Russell's 'Great Western Coaches', Vol.1 and Slinn's 'Great Western Way'
     
    The earliest railway coaches continued many of the design features found in contemporary road coaches. There were no brakes and the frames were of wood, often with papier-maché panelling. Simple square ends and sides were the norm, which makes these 'box' shapes relatively simple to scratch-build.
     
    To help me decide where to start, I have made 'colourised' images of various early coaches, to show how the styles developed.
     

     
    My first group, of 1st-class coaches, suggests that the 'stage coach' style may have persisted longer for these vehicles. They were painted all-over brown until October 1864, when it was decided that the upper panels should be painted white. This became 'cream' after varnishing. Initially, it seems that the white was applied overall, including mouldings, but later, these were picked out in brown. It seems that several older coaches were 'upgraded', losing features such as luggage racks on the roof and acquiring Mansell wooden wheels, for quieter running. By 1872, the 'familiar' style appeared, which set the pattern for very many years thereafter.
     
    It is with this later, more sophisticated, style that the rounded corners to mouldings, now painted black, and the curved 'tumble-home' to sides and ends became established. Other later design features were the looped grab handles and straight-bar door handles, which replaced the earlier 'ring' handles.
     

     
    From around 1854, almost all the coaches that were built were 1st/2nd-class composites, with a separate luggage compartment. 3rd-class accommodation tended to be provided by 'downgrading' older 2nd-class stock. My series of illustrations shows the gradual evolution of the familiar style.
     

     
    Before the introduction of continuous brakes, 'break' (sic) vans were an important component of all passenger trains. As early as 1844, the Board of Trade had recommended that a break should be attached to every fourth carriage and GWR Rule 54 (1865) stated that "No train is to be started from a station without proper and sufficient breaks, lamps, and guards." The provision of a guard's look-out was an important feature, to enable him to observe the state of his train.
     
    So, I have plenty of food for thought and potential for some fairly simple model-building, especially in view of the simple box structure of the earlier designs. The curved window openings of the 1st class vehicles also offer an attractive feature, which can easily be produced by use of my 'Silhouette' cutter. All that remains is to try and establish some dimensions and start cutting
     
    Mike
     
    Next Post
  11. MikeOxon
    Having shown my printed coach sides in the previous post, 'all' I had to do to complete the coach was to assemble the 'box' structure and add wheels. These small tasks have taken some time, as a result of other distractions but, apart from final detailing, I can now show the coach on the track and alongside some later (1870s) GWR designs.
     
    In order to complete the coach body, I needed ends and a floor. I used my 'Silhouette' cutter to make curved-top ends from 20 thou plasticard and cut additional parts to act as compartment separators. The floor is a simple rectangle, cut by hand from 40 thou (1 mm) plasticard. Since the innermost layers of my laminated sides are 20 thou plasticard, It was easy to assemble the body, using MEK-type cement to weld everything together. I fixed one side and one end to the floor first and, when these were firm, added the opposite parts. I then placed partitions at the appropriate places, which also serve to maintain the spacing of the opposite sides, along their length.
     

     
    For the undergear, I used MJT 2299 W-irons (temporarily out of stock again but, fortunately, I had some in hand). I find it easier to make the narrow transverse folds first and then fold the W-irons (opposite to instructions). I mounted one unit on the rocking plate and filled the space between the tabs on the fixed unit with a rectangle of 40 thou plasticard. I marked the centre-line along the underside of the coach floor as well as the positions for the two axles, at 52 mm (13ft equiv.) spacing. I glued the two units to the floor with bookbinders adhesive and allowed to set.
     

     
    The springs are MJT 2248, 4' 6" springs on J-hangers which, unfortunately, come with oil axleboxes. (I may file these down to represent flat-faced grease boxes, but have left them for the moment). I then added sole bars, made from strips of plasticard fixed below the edges of the floor. The MJT 2299 etch includes several detailing items that are useful for representing the fittings on wooden sole bars. I still have to fit the lower foot-boards and there are many other details to add. Since I am considering building the companion all-third coach, which also appears in the 1873 New Milford photograph, I shall probably wait until both are constructed and then add detailing in a 'batch process'.
     

     
    As usual, it is difficult to appreciate the relative sizes of different coaches, from the illustrations in books. I had already noticed how low the sides appeared to be, while I was building the coach, which seems to reflect that the average height of passengers was lower in the Victorian period than nowadays. To visualise the difference more clearly, I included the coach in a train made up from other GWR 19th-century coaches. In the following photo, the coach immediately behind the current one is an S5, dating from 1874, described in a previous blog post This is followed by a clerestory U29, described at http://www.rmweb.co.uk/community/index.php?/blog/1405/entry-13364-six-wheelers-wip-update/. At the end of the train, the light has caught the ducket of a V5 PBV, which I built using 'Shirescenes' sides on a 'Ratio' chassis.
     

     
    I decided to photograph this train from the opposite direction that I usually choose, when photographing North Leigh. My usual choice is partly because it is slightly more difficult to use the camera from the other side but also because I need to do a lot more work on the scenery at the 'Oxford' end! The creamery building can be seen behind the train but the back scene is far from complete, except for a small area around the lime kilns, which can be seen in the background, beyond the narrow-gauge engine shed.
     
    Perhaps showing this view will spur me into doing some more work on the scenery at that end of the layout
  12. MikeOxon
    My previous post in this series about modelling early GWR coaches ended with the comment: " All that remains is to try and establish some dimensions and start cutting."
     
    Since there are several good side-on photographs of these early coaches, it is only necessary to establish one firm measurement and then scale all the other dimensions to this known 'yardstick'.
     
    Rather perversely, I have decided to model a different coach from those I illustrated in the previous post I was looking at a photograph of New Milford, dating from about 1873, which appears in 'Great Western Way' and noticed a line of coaches emerging from the train shed. I scanned a small section of this photo to show these coaches in more detail.*
     

     
    The coach (arrowed), immediately next to the brake van, appears to be very similar to a composite coach that also appears in a good side-on photo in 'Great Western Way', so I have now decided to model this coach.
     
    I chose to take the diameter of the wheels as my reference measurement and my method was to super-impose a dimensioned drawing of a coach with similar wheels and then to adjust the relative sizes, until the two drawings matched up.
     
    All this was achieved by pasting the known drawing as a 'layer' in 'Photoshop Elements', over the photo of my chosen coach.
     
    Once the layers were aligned, I adjusted the overall size of the image, so that 100 pixels represented one foot in the real coach. I then printed the image at a scale of 250 pixels/cm, which resulted in a 4mm scale image of the coach.
     

     
    Now that I had a scale colour image, I could import this into my 'Silhouette Studio' software and add the cutting lines around the windows. (In my case, because I prefer to create an 'industry-standard' drawing, I actually drew the lines with 'Autosketch' and imported the result into 'Studio' as a .DXF file.)
     
    However one chooses to do the drawing, the 'Studio' software is used to add registration marks and the colour image is then printed on good-quality photo paper. I also created an inner layer, with smaller cut-outs for the drop lights in the compartment doors. The printed sheet was then cut out, by means of the 'Silhouette' cutter. Lastly, I cut a second copy of the inner layer in 20 thou plasticard, to provide a support for the two printed layers.
     

     
    As is well known, the 'Silhouette' cutter cannot make clean cuts through 20 thou plasticard, so it was necessary to 'punch out' the individual windows. To do this, I placed one long edge of each window over the edge of my cutting mat and pressed down firmly with one of my wax-carving chisels. This produced a hinged 'chad' that I could then bend, to break it free from the rest of the side.
     
    The final step was to spread a thin film of bookbinders adhesive on the innermost layer and add the next layer, carefully adjusting its position for exact registration of the windows. Then repeat for the top layer, which comprises the coloured coach side. I decided not to cut another layer for the very fine panel edge mouldings but may try adding these with plasticard microstrip, later.
     

     
    The end result of this stage is a pair of complete coach sides, with recessed drop-lights in the doors. Next step will be to complete the box body, with a pair of plasticard ends, and then I shall build the 4-wheel chassis.
     
    Mike
     
    Next Post
     
    * The 1873 photo of New Milford (also in Wikipedia) was presumably taken shortly after gauge conversion. There are many other interesting items of rolling stock, including several different types of cattle wagon, in the foreground.
  13. MikeOxon
    It's been a longer interval than usual since my last entry in this blog. Readers of the forums may know that this is because I recently spent a month in SE Asia and, in passing, took a few photos of the Sabah Railway
     
    Before I left, I had decided to build a brake van to accompany the early 4-wheel coaches that I described in a previous post . Like the coaches, the brake van is based on the photograph taken at New Milford shortly after conversion of the South Wales lines to standard gauge in 1872. There are three vans in the photograph, all of an earlier design than diagram V2, for which an etched brass kit is available from the Broad Gauge Society (BGS). The earlier van is of straight-sided construction and, therefore, seemed a simple task for scratch-building and would, once again, provide me with 'something different'.
     
    While I have now built several coach sides by using my Silhouette cutter to create the panelled detail, I decided to try a different method of assembly for the present coach, which I thought would make it easier to align the various layers. I am pleased to be able to report that this has turned out to be the case and I intend to use this method, described below, for my next build and, possibly, to re-build some of my earlier coaches.
     
    The first step, as usual, was to prepare drawings of the chosen prototype. I do not have a good side-on illustration of the prototype so have had to make several assumptions about the dimensions. In particular, I assumed that the panel sizes were the same as on the later diagram V2 van. The van in the foreground of the New Milton photo shows the layout of the panelling very clearly (different from the V2), whereas one of the vans in the background is the opposite way round and shows more detail of the guard's end. Taking these together, I made the following interpretation of the original vehicle, resulting in a body length of 20' 6".
     

     
    I was unable to read the number on the sides of any of the vans in the New Milford photograph, so chose a number from one of the vans involved in the Shipton-on-Cherwell accident of 1874 . This has the additional advantage that I know this van worked in the Oxford area, where my layout is set.
     
    As before, I designed the sides as three separate layers; the inner having cut-outs to represent the window drop-lights, the next layer being colour-printed to represent the main detail on the sides, and the top layer representing the outside framing. For this model, however, I decided to construct a whole box, so as to create the body first, before applying the outer, cosmetic, layers. This mode of construction meant that I could concentrate on assembling an accurately aligned structure, without risk of damaging any external detail.
     

     
    I used my Silhouette cutter to mark out the sides and ends of the main body shell on 20 thou (0.5 mm) plastic card. There was very little detail cutting required - simply the drop-light for the guard's compartment, one each side, and the end windows. I find it quite difficult to snap out small details, such as windows, when using the Silhouette cutter with 0.5 mm card, so I cut an additional two diagonal lines within the window aperture. By working from the centre of the window, I can fold the resulting triangular sections back, to form a clean break at the edges of the window. A little work with a small round file is sufficient to clean up any roughness at the corners. I assembled the sides and ends around a rectangular floor plate, cut from 40 thou (1 mm) plastic card, using polystyrene cement, to create a firm, rigid structure.
     

     
    Once the cement had hardened, I painted the areas around the drop-lights with Venetian Red colour, where it would show through the window apertures in the detailed side layer. I then attached the side layer, pre-printed on photographic paper and varnished with Humbrol 'Satin Cote', by means of bookbinders adhesive - carefully aligning the window apertures over the drop-lights in the inner sides. Varnishing the ink-jet printed sides is essential, to prevent damage from the water-based PVA.
     

     
    The next step was to add the guard's look-outs, for which I had left apertures in the printed sides (etched brass look-outs are available from the BGS but have a different pattern of framing). I made a 'solid' body for each look-out from a rectangle of clear perspex, filed to form the rounded lower edge and sloping top, where the main roof overlaps the side projection. The resulting plastic shapes were then glued into place on the sides of the vehicle, using a hard plastic adhesive.
     

     
    I had prepared printed front and sides for each look-out, to match the main body, and added these before applying the final layer, which is the outside framing, painted black before attaching to the body. With the printed overlays and outside framing in place, this (somewhat superannuated) small boy was delighted to see the light shining through the guard’s look-out windows ,when lit obliquely! This lighting also brings out the depth of the outside framing, which adds a lot to the 'character' of the model. I have fitted MJT compensated W irons under the floor, which I was pleased to find are back in stock, and I received mine by return of post.
     

     
    Finally a view of the model, lurking in an industrial-looking area of North Leigh, at the back of the creamery.
     

     
    I found that building the body shell first was much better than laminating the sides first, since it meant that the sides received far less handling during assembly and it was easier to align the various layers. I hope the model has more than a passing resemblance to the prototype photographed at New Milford in 1873. There is still work to be done on the under-frame, and I need to find a source of long-shank buffers, but I am pleased that the body has captured the mid-19th century 'look' and will soon be able to run in the 'Ox & Cow' local service to Oxford via North Leigh ...... which reminds me that I still have to complete a tender for No.184
     
    Mike
  14. MikeOxon

    Easy-Peasy Carriage Build

    By MikeOxon,


    General
    Easy-Peasy Carriage Build or ‘How to build a carriage with no drawing, no measuring, and little time’
     
    One of the vehicles I wanted to add to my collection for use with my ‘Firefly’-class locomotive was the early type of 6-wheel ‘open’ 2nd-class carriage. There is a full-size replica at Didcot Railway Centre, as shown below:
     

    Didcot Railway Centre – Replica ‘Fire Fly’ and train
     
    At first glance, those panelled sides might look to be a modeller’s nightmare but 3D-printing makes it extremely simple!
     
    There are drawings of this carriage, by Eddy Lane in the appropriate Data Sheet from the Broad Gauge Society, so my first step was simply to import a copy of his drawing, as a ‘Canvas’, into ‘Fusion 360’. The drawing shows the overall length as 27’ 2½“ (i.e. 108.8 mm in 4 mm/ft scale).  Again, ‘Fusion 360’ makes it very easy to scale the ‘Canvas’ by means of a ‘Calibrate’ command, which simply requires the length of one reference line to be stated.
     
    Now that I have learned about some of the tools that ‘Fusion 360’ has in its armoury, I have realised that there are many aids to creating arrays of similar features, such as the regular panels on this carriage. In fact, I only needed to create four types of rectangle: ( i ) the outline of the complete side, ( ii ) a ‘window’ opening with rounded corners, ( iii ) the upper side panel, and ( iv ) the lower side panel. I simply created one each of the required types, in registration with the ‘Canvas’ . After that, I could use the ‘Pattern’ tool to replicate as many identical rectangles as were needed to complete the entire carriage side! The same method can be used both for the ends and for the internal partitions.
     
    Thus, a few simple steps were all that was necessary to turn a published drawing into a three dimensional model. The overall procedure is illustrated below:
     

    Stages in converting a published drawing into a 3D model, using 'Fusion 360'
     
    I now had three ‘printable’ bodies that I transferred to my ‘Cura’ software, to produce a ‘sliced’ model suitable for my printer. Since these individual components only take a few minutes each, to print, I laid out all five partitions together as a batch, for which the total print time was only 45 minutes.  I also printed the sides and ends in pairs, with similarly short print times.
     

    Set of Printed Partitions created as a single job
     
    To assemble the parts, I fixed the ends and all the partitions to one side, using super-glue, starting from one end and adding the partitions one at a time. I then weighted the assembly until the glue had cured.
     

    Steps in assembling the components parts of the model
     
    After completing this side by adding the final end panel, I applied super-glue to the outer edges of all the partitions and the two ends. I then offered up the remaining side, pressing it into place until the glue ‘caught’. I laid the model on its side and weighted the upper surface until the glue had cured.
     
    To show the end result of less than a day’s work, I added a chassis and a roof from one of the carriages I had already built:
     

    My ‘easy-peasy’ carriage
     
    Of course, there are lots of finishing touches to add. The purpose of this short post was to show how a seemingly complicated design can be created quickly and easily, by making use of the tools available in 3D design software.
     
    Mike
  15. MikeOxon
    In my previous entry, I 'mocked up' photos of various styles of roof that I could apply to some of the existing buildings on my layout. My aim was to re-create the appearance of traditional Cotswold roofs, such as would be found in the countryside around North Leigh.
     

    Houses in Snowshill, Glos
     
    That initial survey led to me replacing the roof on one my buildings with plastic sheet cut from the Wills 'dressed stone' pack (SSMP202). The sheet replicated the way in which the stone courses are widest near the eaves and then diminish towards the apex of the roof After painting with a mix of acrylic colours, chosen to portray the characteristic appearance of real Cotswold roofs, the model took on much of this regional style:
     

     
    Nevertheless, I felt that the plastic sheet looked rather 'flat' and homogeneous, compared with a real Cotswold roof. I happened to read an item on Julia Adams' blog, which showed photos of some buildings at Pendon museum. These buildings are made from card, with each tile applied individually. As readers of my blog will know, I like to look for short-cuts and, in this case, my thoughts turned to the Silhouette cutter.
     
    Details of the construction of a Cotswold stone roof can be downloaded as a PDF from http://www.stoneroof...ate roofing.pdf From this reference, the lowest course uses the longest slates, known as 'cussoms', with a visible length of about 357mm. The next rows are called 'followers', with visible length 216mm. Much smaller slates, known as 'short cocks' are used higher up the roof, with a visible length of only 127mm. My first step was to take a photo of such a roof and then to select individual rows of slates, in the various sizes used for the construction of the roof:
     

     
    I adjusted the size of the image to 4mm scale and then opened the file in the Studio software supplied with the Silhouette cutter. I then added 'cut' rectangles around each row of slates and duplicated the rows to make a sheet of parallel rows of slates. [EDIT - after drawing the 'cut' rectangles by hand, I realise that I could use the 'Trace' function in the software, to do this automatically.]
     
    After adding alignment marks in the cutter software, I printed the sheet onto card, using my colour ink-jet printer. On placing the printed sheet in my Silhouette Portrait cutter, the machine first found the registration marks and then cut out each row:
     

     
    I had thought of using the Silhouette to scribe outlines of individual slates as well but decided that it was easier and quicker to do this by hand, using the tip of a wax carving chisel to emboss the joints. Then I laid the strips on the plastic roof of a building, starting at the bottom of the roof and using the grey bands that I had printed, to set the overlap of each successive row:
     

     
    The finished roof has the advantage that the rows of slates overlap each other, as in a real roof. This is most clearly visible along the edges of the roof, as seen in the following photo of this type of roof applied to my saw-mill:
     

     
    While I quite like the result, it still has a rather 'regular' look and really needs the dedication that is required to cut and fit each slate individually!
     
    I decided to try one final method, which is similar to one I used many years ago, when I first built some of the other structures on the layout. For my final roof, I applied a thin coat of plaster filler to the surface of a plastic roof, using a spatula plus a wet finger, to achieve a smooth finish:
     

     
    I then scribed horizontal courses into the plaster, using a wax-carving chisel and made vertical indentations to mark the individual slates. Finally, I painted the surface of the plaster with a mix of acrylic colours, to achieve my desired effect.
     

     
    I have to admit that, although this is the least 'accurate' of my three attempts, it is my favourite, largely because the texture of the plaster has reproduced the appearance of stone much more effectively than plastic can do. I guess it is a case of 'artistic impression' versus 'technical merit'
     
     
    Finally, I show an overall view of the 'quarry end' of my layout with all three roofs visible. The narrow gauge (009) line that meanders between the buildings is largely invisible between the various stone walls:
     

     
    Mike
  16. MikeOxon

    Extending my 3D Modelling

    By MikeOxon,


    General
    3D- Printed Track Base
     
    At the beginning of the year, my thoughts turned towards making some track for my Broad Gauge (BG) models. I have already built a short section of track using traditional methods but I decided to see if 3D printing could help.
     
    After some experimentation in the early days of the GWR, the design of prototype broad gauge track settled into the form shown below:
     


    Construction of Broad Gauge Track
     
    The longitudinal baulks were about 30 feet (~ 9 m) long and held at the correct separation by transoms placed at around 8 foot (~ 2.4 m) spacing.
     
    For modelling purposes, I created baulks of 120 mm length, with 4 transoms evenly spaced in each section, so that individual pieces can be butted together, while maintaining constant spacing of the transoms. Creating a 3D model in ‘Fusion 360’ was straightforward, by extruding from a plan-drawing to a depth equivalent to the prototypical 7” (~ 18 cm). I added some surface detail to represent the short packing pieces that were placed immediately below the rails themselves.
     
    Once extruded, the 3D model appeared as below:
     


    My 3-D Model of a section of BG Track
     
    Remembering my old ‘Tri-ang’ track, with its grey plastic base representing the ballast, I thought I would see if it would be possible to 3D-print the ballast. It proved to be far from simple but opened up a whole new aspect of printing with 'Fusion 360'!
     
    Creating Surface Texture in ‘Fusion 360’
     
    I soon found that there appears to be no simple way of adding surface texture in ‘Fusion 360’ – it can be added as a visual effect for on-screen display but not in a way that can be 3D-printed. So, I started researching by means of Google, to see if there were any ‘work arounds’.
     
    I found several references to a ‘plug-in’ for 'Fusion 360' called ‘Image2Surface’. This adds a capability for 'Fusion 360' to create a textured surface from a 2D image. Downloading the appropriate software and then getting it to work was not straightforward but, fortunately, I found a 'YouTube' video, which explains the procedures very well – see: https://www.youtube.com/watch?v=ChdJ8nL7qQA
     
    Warning. The next few paragraphs are rather technical and largely an aide memoire for myself. All the information is in the video above.
     
    At first, I had to keep listening to short sections of the video and then trying one step at a time.  For reference, I have made the following précis:
     
    The first step is to download a zip-file containing the software  Fusion360Image2Surface-master.zip from the Autodesk Knowledge Network. Mine is the Windows 64-bit version but there is a version for Mac as well.
      On my Windows machine, the downloaded zip-file has to be extracted into the ‘Fusion 360 Addins’ folder, where the extracted folder must be re-named to ‘Image2Surface’. The Addins folder is typically located at C:\Users\’user name’\App Data\Roaming\Autodesk\Autodesk Fusion 360\API\Addins
      Within the running 'Fusion 360' application, open the ‘TOOLS’ menu and then open the ‘Addins’ drop-down box to select ’Image2Surface’. There is a check box to open this addin automatically whenever 'Fusion 360' starts.
      Once the addin is running, simply click on its icon and a new window opens in 'Fusion 360'. This allows you to open a standard JPEG image from your computer. There are various adjustments available, to make sure it has an appropriate amount of detail.
     
     
    Once the settings have been made, click on ‘Generate Surface’. The next process may take some time, depending on the complexity of your image, but eventually an image will appear on the main 'Fusion 360' screen.
     
    At this point, there are still several steps to be taken before you have a 3D-printable object.
     
    The surface created by the addin has now to be converted into a ‘body’, which involves several stages, as listed below:
     
    Open the ‘SOLID’ menu and then click on the ‘Create Form’ icon in the ‘CREATE’ section.
      A new series of icons will appear. Click below the ‘UTILITIES’ icon to open a drop-down menu.
      Click on ‘Convert’ in the drop-down menu.
      In the box that appears, select ‘Quad Mesh to T-spline’ in the ‘Convert Type’ selection box, then choose the ‘Select’ button and click on your design. Click ‘OK’ to create a new ‘body’.
      At this stage, there are various clever-looking options in the drop-down ‘MODIFY’ menu but I haven’t explored any of these yet.
      To complete the conversion, click the ‘FINISH FORM’ button. There may be another long wait, at the end of which you have a new body but it is still only a surface and is not yet printable.  
    By now, if you still reading, you are probably feeling ready for a stiff drink but hold out just a little longer!
     
    To make a stand-alone solid object from a surface, create a profile plane below the surface object created by the plug in.  In my example, the subject is rectangular, so I drew a rectangle on the X-Y plane below my object, as shown in the following illustrated steps:
     


    Stages in creating a 3D model of ballasted BG track in 'Fusion 360'
     
    Once I had a solid ‘body’ in 'Fusion 360', I could add this to my model of Broad Gauge track, shown above. It does indeed look quite like the old Tri-ang track!
     
    Of course, I realise that, in most cases, 3D printing is not a very sensible way to create ballast and traditional methods are more effective and probably easier to create.
     
    Potential Applications for Surface Modelling
     
    I believe that the real significance of having found this method of creating a 3D surface textures in ‘Fusion 360’ is that it opens up all sorts of new possibilities for model-making.  Ideas that spring to mind immediately are surface finishes, such as stone or brickwork on buildings – these could easily be derived from photographs of real buildings. A search on the web for ‘greyscale depth map images’ shows plenty of examples, many of which could be applied as architectural features:
     


    Examples of Depth Map Images from Google
     
    Another possibility is to create 3D nameplates. I found that, by starting from a photo of ‘Rob Roy’ (an engine I have previously modelled), I could convert the actual name plate into a 3D printed model, as shown below:
     
     

    My 3D-printed nameplate on the printer bed.
     
    Unfortunately, the resolution of my basic FDM printer is insufficient to reduce this to 4 mm scale; the example shown is around 7 mm scale and the detail becomes blurred if I make it smaller. Nevertheless, even with a simple printer like mine, station name plates, shop signs, and the like should all be realisable in 4 mm scale.
     
    For fun, and in anticipation of a more cheerful year in 2022 , I copied an image of the frieze high above the entrance to the Paddington Station hotel!
     


    Paddington Hotel Entrance (created from Google Streetview)
     
    There are good detailed illustrations of the frieze on this website: http://www.speel.me.uk/sculptlondon/paddingtonstation.htm , including an engraving of the pediment, designed by John Thomas in 1854. According to the website: “John Thomas, a now little known but extremely good sculptor, shows his skill at composition in this work. There are 10 full sized figures in the pediment, of which two are seated on one side, one on the other, and three large animals, and yet a perfect balance between the two sides is maintained.”
     
    Of course, it was a very ambitious subject to attempt but I simply copied the engraving shown on the above website, increased the contrast a little, and read it into the ‘Image2Surface’ software. Since the original was not a ‘depth map’ image, I could not expect a highly accurate rendering. The depth of the relief depends on the brightness of the image, so some work to bring forward selected parts of the image, by making them lighter, and to recess others, by making them darker, could help to improve the result.
     
    I converted the image into a sold body, using ‘Fusion 360’ exactly as described above. I then transferred the file to my ‘Cura’ slicing software and prepared it for printing. This resulted in a rather large file and, at first, it seemed to give my printer ‘indigestion’, as it didn’t want to start on my first attempt. After a re-set, it started up, although it initially indicated a print time of 15 hours!  Fortunately, this proved to be a dramatic over-estimate and the print actually took about 50 minutes, to produce the following result:
     
     

    My 3-D printed model of the Paddington Station Frieze
     
    It’s not exactly Hi-Fi, partly due to the limitations of the original image, which was not intended for this purpose, but it would make an interesting addition to a model building.
     
    I think there is plenty of food for thought here, to influence my modelling in 2022.
     
    Mike
  17. MikeOxon
    I thought it would be easy to modify my U29 model, to represent the body of a diagram G13 Family Saloon but various gremlins struck with a vengeance!
     
    Omit reading the ‘Gremlins’ sections, if you just want to follow the progress of the model itself.
     
    Gremlins
     
    I have now learned the necessity for taking great care when selecting entities to modify in Fusion 360.
     
    For example, when selecting parts of a drawing in, say, the X-Z plane, it is easy to include parts of a drawing that are in the Y-Z plane, by mistake.  So, unintended changes are made to the ‘other’ drawing as well.  I think this explains how I managed to lower the height of the clerestory, without noticing until I had done a lot more design work.  Although I could ‘go back’ to the point where the problem started, I still had to re-do all the work on the window apertures and partitions, to fit the corrected body shell.
     
    I have also found some difficulties when importing old DXF drawings into Fusion 360.  Some panels, which had seemed to be ‘closed’ in other software, could not be extruded.  I eventually spotted some very tiny gaps, which I managed to fill, although I am still not sure exactly which incantations are needed to make the ‘extend’ command work on drawings imported into Fusion 360.  I had almost given up, when the command suddenly started working, for no reason that I could determine!  
     
    Having modified the drawing, I tried to save it and this brought up a message that “This file type requires cloud translation, which may take a few minutes.”.  For some reason, the ‘translated’ DXF file was unreadable in other programs, such as Studio, Autosketch, or Irfan View.  In the end, I decided to go back to Autosketch and repair the file there, so that it now works correctly in both Fusion 360 and other programs.  
     
    I mention these things, to show how learning 3D CAD programs can be very frustrating.
     
    Printing the G13 body and clerestory
     
    Once I had modified my carriage design to represent diagram G13, I printed the body and roof, as previously described for my U29 carriage.  
     

     
    This time, however, I wanted to investigate how I might use the 3D printed body as a basis for ‘finishing’ with parts produced on my Silhouette Portrait cutter.  For this reason, I omitted the inset panel details, which I had included in my U29 model, and left the outer surfaces smooth.  I did, however, include other inset items, such as window apertures and drop-light frames.
     
    3D-printed Carriages
     
    There’s nothing really new in this – I’ve simply substituted a robust 3D-printed body shell for the relatively frail laminated plasticard that I had used before.  I am impressed by the toughness of the PLA plastic.  It’s supposed to be bio-degradable, however, so perhaps it will crumble away in a few years time – I’ll leave it to my Grandchildren to find out!
     
    My planned method was to use my Silhouette Portrait machine, to cut out the body framing from 10thou (0.25 mm) plasticard, and my HP Inkjet Printer to print overlays for the body sides.  The ‘registration’ facility of the Silhouette Cutter could then open up the window apertures in these overlays, in registration with the printed body sides.
     

    The Three Printers used for This Project

    For most of my earlier carriage building, I printed coloured sides onto HP Photo Paper, although I did carry out some experiments into printing directly onto plasticard (described in posts in JCL’s Silhouette Cutter thread)  I found some of my old ‘printed-on-hairspray’ samples in a drawer and they still look fairly good – better than I remember achieving at the time.
     
    The actual printing and cutting procedures were exactly the same as I had used previously, when building my earlier versions of these carriages.  To summarise:
     
    “Open the colour image in Studio, copy it and paste it into the cutting diagram. Use the 'Arrangement' command to sent the image to the back and then re-size and align the image with the cutting marks as accurately as possible on the screen (use a magnified image and make sure that 'Snap to Grid' is 'off'). Once you are content with the alignment, turn 'on' the Registration Marks in Studio and Print the image on your colour printer, using the highest print-quality settings. The print-out will include the alignment marks, which will be read by the Silhouette cutter so that the various apertures will be aligned with the colour image.”
     
    I already had all the necessary drawings in DXF files and the colour images as TIFF files, so I could simply open these in Silhouette Studio.  The only differences from my previous method were that I printed the colour overlays onto printable vinyl and cut the frames out of 10thou plasticard, to be applied on top of the vinyl sheets.
     
    Finishing the Model
     
    The first task in finishing the detailing of the 3-D printed body was to cut out the frames, using 10thou (0.25 mm) plasticard.  After cutting out, which the Silhouette cutter handled very well, I painted the frames black and hung them on hooks to dry.  If I were making a lot of these, I would try to source some black plasticard.
     

    Silhouette-cut Frames
     
    Next I printed the body sides from the Silhouette Studio software, using my HP ink-jet printer.  I found, after the first test, that the colour setting of my printer needed to be re-adjusted for printing on vinyl sheet, since what should have been ‘chocolate’ came out more like ‘Indian red’.  After a couple of test prints, I achieved a more acceptable colour for the lower body sides.
     
    I had found before that the vinyl does not stick well to the body shell after spraying with grey primer so, while painting around all the window opening in Indian Red,  I decided to continue painting the whole side with enamel, hoping it would provide a better surface for attaching the vinyl.
     
    It was quite tricky to get the vinyl sheet into good alignment with the window apertures, since there is no ‘slide’ and the adhesive grabs very quickly.  As it happened, the first attempt went well but it does need considerable care!  The clerestory was particularly tricky because I had to tuck the top edge under the roof overhang, for which I used cocktail sticks to push the vinyl layer into place before tamping down over the rest of the side.  It was good to have painted the entire sides first, as any very slight mis-alignment round the windows was not apparent.
     
    Finally, I had to decide how to attach the outside frames, which are rather ‘floppy’, since they are just a skeleton of narrow beadings.  I did not want to damage the appearance of the printed vinyl sides by applying excess adhesive.  I decided to go back to the can of hair-spray that I bought some years ago for experiments on printing directly onto plasticard.  It acts as a mild ‘hold’ adhesive while leaving no visible traces on the surface and I was pleased to find that, in general, it worked well, although adhesion in a few places was poor.  I felt, however, that once the main part of the frame was correctly positioned, everything could be made firmer by applying an overall coat of varnish.  This was another very tricky part of the assembly and the alignment on my first attempt was not perfect.  The ‘First’ lettering on the doors is not quite centred within the frames.  I shall continue to experiment, if I try further assemblies of this type.
     
    Conclusions
     
    Overall, this method of construction worked well.  I haven’t really broken any new ground, since I have previously added new printed sides and framing to one of the well-known Ratio carriage kits.  The only new aspect in the current model was in using all-plastic materials, rather than photo-paper and card.
    Perhaps I would have felt a greater degree of satisfaction if I had built a new type of carriage, rather than repeating one I had made before.  There is no doubt that the use of a 3D-printed body has resulted in a much stronger overall structure.  I’m sure this could be achieved for Silhouette-cut sides by laminating more layers, although that approach brings risks from warping and mis-alignment.
     
    A photograph, which had previously cruelly revealed the defects in my earlier carriages, does show that the new overall structure, especially the clerestory roof, stands up well to close scrutiny.
     

    G13 Family Saloon – final details to be added
     
    For this photo, I placed the body on the Cleminson chassis that I built several years ago for my original Family Saloon.  I have nostalgic feelings for the older carriage, which now has a well-worn look but is noticeably out-of-true in several places.  The really huge advantage of the 3D-printed body lies in the clerestory roof, which I never managed to fabricate well.
     
    From my point of view, it was all part of a learning exercise, helping me to feel more confident in tackling more complex shapes, where the 3D-printing method will come into its own.  I shall now switch my attention to such structures.
     
     
    Blanche Wilcote is pleased that the new carriage is much less draughty than the old one, which had various gaps along the seams!  So that is some reward for my efforts
     
    Mike
     
  18. MikeOxon

    Field Research Trip

    By MikeOxon,


    general
    When I decided to base my layout around the never-built line to Witney through North Leigh, it was simply a whim, derived from a map shown on Martin Loader's website about the Fairford branch.
     
    As I have got 'drawn in' to the scenario, I have begun to learn more about the area and have found, to my surprise, that some of my 'fiction' is closer to the truth than I thought. My layout incorporates several 'features', including a quarry, saw-mill, and.lime kilns.
     
     
    From studying maps, I knew that all these items were present in the area so, as a break from too much time bent over a workbench, I decided to make a 'field trip' to carry out some prototype research.
     
    An initial web search revealed that the remains of a limekiln still exist at the village of Fawler, close to the OW&W main line. The kiln is now a grade II listed building, described at http://www.britishlistedbuildings.co.uk/en-252462-lime-kiln-at-sp-3688-1730-fawler-oxfords
     
    On my visit, I chose the wrong route to approach and, after fighting through dense brushwood, found myself on top of the kiln. I scrambled down the slope for a view of the face and also noticed that there seemed to be an old trackbed at the foot of the slope, running alongside the River Evenlode. Further on, I found much more evidence of old workings, including quarry faces and loading bays!
     

     
    When I got back home, I looked up some old OS maps of the area and found, to my complete surprise, that there had been a branch line to the quarries and kiln, off the OW&W main line! With the exception that my model is narrow gauge, it seemed as though my 'fiction' was turning into reality.
     

     
    On a beautiful sunny afternoon, I continued my exploration of the area and took a photo of the view across the valley below North Leigh, where the railway would have run towards Witney, before meeting the high ground around New Yatt, where my layout provides a tunnel.
     

     
    In North Leigh itself are the remains of a Windmill, which I shall try to include in my back-scene. There is also a preserved sawmill in the area that can be visited - see http://www.combemill.org/
     

     
    Finally, I drove across the valley to Wilcote, where the Manor still stands. To avoid intruding on the privacy of the present owners, I shall show one of Amy's paintings. Nothing much seems to have changed since the 19th century!
     

     
    A very useful and inspiring day's research, which encourages me to spend more time on detailing of the layout itself. I still have my Andrew Stadden figures of the Wilcote family to paint, as well - perhaps Amy and Blanche will soon have their new dresses 🙂
     
    Mike
  19. MikeOxon

    Figure Painting - First Steps

    By MikeOxon,


    general
    Last Saturday I visited my local model railway exhibition - AbRail 2015. I was looking for ideas on scenery and there was a good number of interesting layouts. Several featured canals and water and, of these, I particularly enjoyed the 'Aldford Brewery' (Wimbledon MRC) and the canal-side inn at 'Mulldale' (Letchworth MRC).
     
     
     
     
    I also thought that there were some impressive trees alongside 'The Abingdon Branch'. Initially I thought 'Highclere' (Julia Adams) looked rather sparse but then I came to realise how superbly 'realistic' this model is. The highly-compressed layouts, of which mine is an example, might pack in some interesting 'vignettes' but, overall, they are far from realistic.
     
    I took the opportunity for a chat with Julia and she deftly re-assembled her 'City of Truro' from its components, as I watched. The seemingly effortless way in which it all fitted together made me think how coarse my own efforts are, and the quality of the engineering that makes such precision possible at 2mm scale! I mentioned my own trepidation at starting painting the figures for my own layout and she pointed out that the important thing is to make a start and then 'practise, practise, practise'.
     
    So, with that encouragement, I have taken the plunge and applied a paintbrush to the first of my 'Edwardian/Victorian' figures. I chose to practise on some 'Langley' figures, in the hope that I can develop enough skill to do reasonable justice to the Andrew Stadden figures that I bought last year.
     
    I initially sprayed the figures with grey primer and then decided to use artists' acrylic paints for the actual colouring. I have a good set of sable brushes and, for this task, chose to use a Size 00 brush from the Winsor & Newton 3A series. These brushes have good 'body' to hold a reasonable amount of paint whilst maintaining an extremely fine tip.
     
    I decided to hold the model for painting in a 'Model Craft' universal work holder. This tool has a nice wooden handle, which gives a firm grip, while allowing the model to be turned around easily during painting. I secured the base of each figure with a small lump of 'Blu Tack', pressed into the mounting ring.
     
    I read somewhere that it is a good idea to start by painting the faces, so the first step was to mix a suitable flesh colour from mainly White, plus a little Azo Yellow and a very small 'touch' of Alizarin Crimson. I thinned the mix a little with water and a drop of iso-propyl alcohol, to improve the flow.
     
     

    My Painting Set-up
     
    The other essential tool (for my eyesight, at least) is an illuminated magnifier. The fine tip achieved by the sable brush really makes it quite easy to put the paint in the right places!
     
     

    (photo by R. Flemming)
     
    I used the flesh colour to paint the faces and hands of all the figures in my Langley set and then concentrated on completing the figure that I chose to represent Blanche Wilcote. I looked at illustrations in 'Dame Fashion- Paris-London (1786-1912)' by Julius M.Price, referred to in a previous post in my blog, and mixed what I felt were appropriate colours for the period. After applying the main colours, I then picked out some details in the dress and hat, to produce the result shown below:
     
     

    Blanche Wilcote (1st attempt)
     
    I'm really quite pleased with this first attempt, though I need to work on providing more realistic details in the face. Having 'broken the ice', I can now settle down into working up my technique on the other 'Langley' figures and then I may feel ready for the Stadden set. At least, I can keep Blanche's petulant pleas for new dresses at bay for a little while
     
    Mike
  20. MikeOxon

    Finding some details

    By MikeOxon,


    General
    I visited the Forest of Dean recently to see the site of the Bullo Pill accident and to try and unearth more information about the area. The 'Gage Library' at the Dean Heritage Centre in Soudley holds a large number of maps and books, with staff who are very willing to help.
     
    I have already posted one of my photos of Cockshoot Bridge, close to the accident site and couldn't help thinking that there was a resemblance between the modern LED signal and a Brunel 'disk and crossbar' signal. The Class 66 looks a fairly tight fit within the bridge, so I think the clearance must have decreased from the original broad gauge dimensions. Two things may have happened: the track bed has probably been raised, through adding layers of ballast, and the brick lining is probably not original. I suspect that the bridge was originally constructed more like the one below, which I photographed on the Forest of Dean Central Railway (now a cycle-track)
     

     
     
    I found another old photograph of the accident near Bullo Pill in the Gage Library. This shows how the locomotive 'Rob Roy' rode up over the brake van and cattle wagons of the train ahead of it. The photo must have been taken very shortly after the accident, since the carcasses of cattle are still lying alongside the track. Several interesting details of the track-bed are visible, including the transoms both within the gauge and between the two tracks. The ballast is quite coarse and not heaped to the top of the baulks. In addition, there is no sign of a vee-shaped central drain, as suggested in drawings that I have seen. The absence of this last feature will make modelling the track somewhat easier!
     

     
     
    Among the details visible on the locomotive itself are two white diamonds painted on the front buffer beam, .
     
    I also found a photograph of the opposite side of 'Rob Roy' from that seen in the accident photo, shown in my previous post. The locomotive appears to be in similar condition to that in the photographs of the accident and also shows the white diamonds on the buffer beam.
     

     
    The detail in these old photographic plates is quite remarkable, with plenty of information to guide the modeller. For example, the Salter spring balance for the safety valve, and several footplate details, are visible in this crop from one of the accident photos.
     

     
    Taken together with Mike Sharman's scale drawing of 'Lalla Rookh', another member of the 'Waverley' class, I feel that I have everything needed to make an attempt at a model of this type of engine.
     
    Fortuitously, the RCTS volume covering Broad Gauge locomotives (Part Two), states that the boiler and firebox of the 'Waverley class' engines were identical to those of some of the Gooch 'Standard Goods' engines. Since there is a Broad Gauge Society kit to build a 'Standard Goods', I intend to see whether this kit can form the basis for a model of 'Rob Roy'. It still leaves, however, the interesting problem of modelling the curved splashers over the exposed driving wheels!
     
    In any case, the other locomotive involved in the Bullo Pill accident was 'Tantalus', a 'Standard Goods' engine, so I could also use the BGS kit to build this locomotive. The boilers of these locomotives were very large, compared with the standard-gauge' engines of the day. The boiler dimensions are given in the RCTS book as 11' (3.35 m) in length and 4' 6" (1.37 m) in diameter, with a firebox casing measuring 5' 0" X 5' 4" (1.52 X 1.63 m) and a grate area of 19.2 sq. feet (1.78 m2). The following photo, shows 'Zetes', a sister engine to 'Tantalus, in Gloucester, from where it probably also ran on the South Wales route.
     

     
    There's certainly no shortage of detailed information to guide my modelling activities, so I can now start to prepare some detailed plans.
     
    Mike
  21. MikeOxon

    Fire Fly class - Part Five

    By MikeOxon,


    General
    Adding some details
     
    After a rather intensive period of model building, I’ve slowed down a little, while other activities have called for my attention. The train of early Broad Gauge vehicles, including the Posting Carriage etc. still raise a smile as I pass by them on their shelf. They are, however, still waiting for their engine, so I need to press on with my ‘Fire Fly’ class model.
     

    my three recent GWR Broad Gauge models
     
    I always find that momentum is easily lost, once the main structures have been completed and several major design problems have been overcome. Nevertheless, there are still several tricky areas, such as the brackets that support the boiler, smokebox and firebox above the outside frames.  Some of these small parts need as much design effort, or more, as the larger items.
     
    I decided to make a list of parts that I would construct as my next objective, to provide a focus for the next phase of this build.
     
    For the body, my list includes:
     
    support brackets for the boiler chimney and safety valve cover front buffer beam and buffers  
    For the chassis, there are the wheels and inside motion.
     
    These items should create the overall appearance of the engine, leaving various small items, such as water feed pipes, handrails, and controls to be added.
     
    In this post, I shall cover the ‘body’ items and leave the chassis for next time.
     
    Support Brackets
     
    When I started to think about the brackets, I was by no means sure that my 3D-printer would be able to create these rather delicate structures, which is what they become at 4mm scale.  I found a couple of drawings, shown below, that provided the details of these brackets.  I have used these as the basis of my designs.  The brackets at the smokebox and firebox sides are similar to one another but different from the central brackets that support the boiler.
     

    Fire Fly Brackets – (left) Firebox and Smokebox, (right) Boiler support
     
    I decided to start with the end brackets, as I felt these were potentially easier to create. I had already marked the positions on the sides of the smokebox and firebox, to provide reference points for attachment of these items.
     
    I brought up a front view of my 3D model of the smokebox in ‘Fusion 360’ and drew the bracket lines and circles with reference to the main model. After drawing the cross section of the bracket, I used the ‘push/pull’ tool in ‘Fusion 360’ to create a solid object. My test print showed that they could be reproduced very effectively by my ‘Geeetech E180’ printer, despite their very small size, as shown in the following photos. Incidentally, the set of four brackets took only 5 minutes to print and they were ready for immediate use – no post-processing was required.
     

    My 3D-printed Brackets as printed and then attached to the Smokebox
     
    The design of the central boiler brackets presented another challenge in that, on the prototype, they provide direct support to the boiler itself and, therefore pass through the cladding. This can be seen in my photograph of the Fire Fly replica at Didcot, below:
     

    Fire Fly replica
     
    I decided not to attempt threading my model bracket through the cladding but to truncate the design at the outer surface, I did, however, decide to show the plate at the top of the main strut, as this is how it appears in my reference photo of ‘Argus’.


    My 3D printed Boiler Bracket (attached to cladding)
     
     
    Chimney and Safety Valve Cover
     
    I 3D-printed both these items, using the methods I have described in previous posts:
     
    For details of how I created the chimney see this post: For details of how I used the ‘revolve’ tool for safety valve covers (and domes) see this post:  
    As I build more models, I find I can draw on previous designs to solve many problems and I frequently refer back to my earlier posts as aides memoires.
     
    Front Buffer Beam
     
    The font buffer beam is a simple rectangular bar from which I extruded two cylinders to represent the leather buffers of the period.
     
    Assembly of my Fire-Fly class ‘body’
     
    Adding these details to the main components of the body was straight-forward.  I used 'superglue' to attach the brackets into the prepared recesses on the sides of smokebox, boiler, and firebox. I had been concerned that the contact area might be too small for successful bonding but, in fact, after allowing time for the glue to polymerise, they proved to be very firmly attached indeed.  I provided the bases of the chimney and safety valve cover with spigots, which fitted into holes provided for them.
     
    For attaching the buffer beam, I used my tried and tested method of running a low temperature (200°C) soldering iron tip along the inside joins, to weld the parts together.
     
    The model shown below has a good solid 'feel', contributed by the brass tube that forms the boiler underneath the cladding.
     

    my model of a Fire Fly class engine
     
    Computer Visualisation
     
    To help visualisation of the planned end result, I colourised the various parts I have made so far on the computer screen. Such views provide plenty of inspiration to keep me going
     

    3D computer model of the Fire-Fly class body
     
    Mike
  22. MikeOxon
    Angled Spokes
     
    I ended the previous part of this series by noting that my next subject would be wheels. This subject, once again, raised questions as to what were the real facts! An ‘official’ GWR drawing shows alternate spokes sloping in opposite directions between hub and rim, as below :
     
     

    Drawing of ‘Firefly’ Driving Wheel
     
    On the other hand, another ‘official’ plan view of the frames shows one set of spokes fitted radially, while the other set is angled. Commenting on this latter drawing, shown in his book on Broad Gauge Engines (Part Two), Brian Arman writes that “the inner [spokes] are visible, inclined inwards to take advantage of the extra space permitted by the broad gauge and provide a deep strong hub. The outer spokes are vertical but concealed by the tyre”
     
    Whichever is the correct view, the sources agree that the spokes were inclined in some way,which presents problems for making a 3D print by the ‘Fused Deposition’ method.
     
    Before considering the printing problem, I also had to prepare a 3D drawing of a wheel of this type. For the record, I used the above drawing of the wheel as a ‘canvas’ in ‘Fusion 360’, drew a single spoke and then used the ‘pattern’ tool to create a ring of 14 spokes. I then drew an intermediate spoke and used the ‘move/copy’ tool to set it to an appropriate angle. I repeated the pattern to create the second ring of angled spokes. These steps are illustrated in a clockwise direction below:
     

    Drawing spokes in two rings, using the ‘pattern’ tool in ‘Fusion 360’
     
    Having found that my printer could handle a limited amount of overhang, I tried printing this wheel but it failed to complete the raised ends of the angled spokes, as I had expected it would 
     
    Two-part Wheel
     
    Another pause for thought and I hit on the idea of splitting the wheel into two halves. I found that I could flex the rim sufficiently against the hub to vary the angle of the spokes, so I printed two sets of flat spokes. What would become the outer part of the wheel carried the main depth of the rim. The inner part had a shallower rim of larger diameter, to represent the wheel flange. I raised the hub of the inner part to act as a spacer from the front part and then pressed the flange outward to meet the main rim of the front part.
     

    My design for two wheel ‘halves’ in ‘Fusion 360’
     
    The two parts printed successfully but I could not use my favoured jointing method of applying a 200°C soldering iron in the confined spaces between the spokes. Instead, I threaded the front part onto an axle, added a thin film of superglue on the inside face of the hub and slid the inside part of the wheel along the axle until the hub was firmly against the front part. Once the glue had ‘set’, I worked around the rim, pressing the two parts together over a thin film of superglue. I found that superglue does appear to be very effective when used on the PLA plastic. The only tricky part lay in ensuring that the two rings of spokes were in the correct alignment.
     
    Once assembled, my 3D-printed wheel looked as shown below. The angled spokes can be seen at the back of the wheel:
     

    My 3D-printed Wheel and Profile
     
    I was pleased to achieve this result, although I shall admit that there was a period of trial and error, while I adjusted the dimensions to achieve the correct-looking profile.
     
    Since each pair of ‘halves’ only took around 8 minutes to print, the experimentation was not too arduous. I found that the inner section tended to print slightly thinner than the planned dimensions, probably because of the effect of adhesion to the printer bed. I had planned to make the wheel 2 mm depth but my first prototype measured only about 1.65 mm on my micrometer, so I increased the depth of the flange to compensate.
     
    Contemporary Sketch
     
    In replying to comments on my previous entry, I referred to the work of E.T. Lane, which I repeat here:
     
    E.T. Lane was a pupil at Swindon in the 1840s, who sadly died at the age of 20. Fortunately for us, he made many sketches of the engines he saw in the yard at Swindon during the late 1840s. I can imagine the young lad standing there, looking at these new engines and transmitting his vision to posterity.  They seem to convey more 'feel' for their subjects than finished technical drawings.  The inclusion of dimensions makes them very useful to modellers, although some are hard to read.  I like his youthful flamboyant signature too. Amongst the engines he sketched was ‘Gorgon’, one of the ‘Fire Fly’ group built by Fenton, Murray and Jackson and delivered in November 1841:
     

    ‘Gorgon’, sketched by E.T. Lane in 1848
     
    I feel that he has left us a real link with the past, to stand alongside the early photographs by Fox Talbot and others.
     
    Smokebox Rivets
     
    To conclude this phase of my modelling, I added some of the details to the front of the smokebox. While there are several drawings of the plan and side elevation of these engines, there is less information about the front elevation. I turned to the lithographs of J.C. Bourne and to my own photographs of the replica at Didcot (remembering that this is not a totally reliable source of prototype information).
     

    My photo of the Didcot ‘Fire Fly’ Replica
     
    Following my usual method, I overlaid a drawing of the components on the front surface of the firebox, allowing for the perspective from which my photograph was taken. Note that the curved top to the door also appears in lithographs by J.C Bourne.
     
    I overlaid my drawing onto the front of my 3D model in ‘Fusion 360’ and used the drawing tools to copy and then extrude the main features. For the rivets around the edge, I used the ‘pattern on path’ command, after drawing the outline as an initial guide. This is a very effective way of adding repetitive details to a drawing in ‘Fusion 360’.   I know that I have added too few rivets but I have to allow for the limitations of my 3D printer in resolving fine details. My intention is to convey the impression of a riveted edge. The current version of my model is shown below:
     

    My model with Smokebox Door details
     
    There’s still quite a way to go and I must think about putting something between those widely-separated Broad Gauge frames! I’m getting so absorbed in this model that other household tasks are becoming neglected
     
    Mike
  23. MikeOxon

    Fire Fly valve gear

    By MikeOxon,

    I joined my grand-children for a visit to ‘Thomas the Tank Engine’ at Didcot Railway Centre on 7th October. During the afternoon, I slipped away for a while, for a look inside the Broad Gauge shed.


    Fire Fly replica at Didcot

    After my exploration of early valve gears, while working on my 'Waverley' model, I decided to look at some gear 'in the flesh', so to speak, since I find it hard to read engineering drawings sufficiently well to get a real 'feel' for the hardware,.

    It's always a bit of a shock to make the transition from tiny slivers of brass and strands of wire, to the reality of 12" to the foot scale. Those tiny levers and shafts turn into rather hefty lumps of iron. As someone once commented "real valve gear ain't so dainty"

    It seems a pity that this splendid replica locomotive, which I watched having so much care and attention lavished upon it, now seems to be left at the exposed end of its shed, where corrosion and accumulation of debris are taking their toll. As my photos show, there are various old cans amongst the motion, which may be covering various oil cups, as well as providing homes for several spiders, with their extensive webs. I've not tried to use Photoshop to clean-up the artefacts, in case I falsify some hidden components.

    To start with a drawing: 'Fire Fly' has gab motion, which is clearly derived from the layout used by Stephenson on 'North Star'. There are three transverse shafts, the central one being called the 'weigh bar' which carries the levers that operate the valves, and two others, arranged to raise and lower the gabs so as to obtain either forward or reverse gear.

    EDIT 11th.Oct. - I have cleaned up this drawing a little, to clarify the linkages to the gabs and forks, while removing some extraneous lines. This has made it clear that the reverse eccentrics are towards the outsides of the engine and the forward eccentrics towards the centre.


    Fire Fly valve gear

    The drawing shows the arrangement, which ensures that, when the reversing lever is operated, one set of gabs is lowered and the other is raised, to engage the valve operating mechanism. The large forks guide the gabs into position, removing the need for manual alignment of these parts. The three transverse shafts are marked in red.

    Turning to my photos of the Didcot replica: a lot of the details are hidden by the frames, since the photos were all taken from the platform alongside the locomotive. These views are from the right-hand side (RHS) of the locomotive, with the wooden boiler cladding visible at the top of each frame. The forward eccentrics (with the gabs engaged) are near the centre-line of the locomotive.

    Each side of the two-cylinder engine has the motion for its cylinder carried between bearings mounted on two frames, so that there are four frames across the whole width of the engine. Achieving precise alignment of all the bearings in these four frames must be a critical assembly task. The use of these multiple frames does, however, reduce the load on each frame and this helps understanding why they look somewhat insubstantial, in comparison with later plate frames.



    I found it was very useful to see how the transverse shafts are supported in bearings carried on shaped pedestals above the frames. The bearings themselves are then held by keepers, with adjustment bolts.



    A horizontal view across the width of the engine shows the shafts running through the bearings on every frame. In between, the tips of the forks which 'grab' the valve rods when the appropriate gear is engaged can just be seen, although the main rods from the forward eccentrics, with their gabs (notches) are unfortunately hidden.



    A more oblique view taken from near the front right-hand side of the locomotive shows the layout of the linkage to the valves more clearly. The arched bracings between the inner and outer frames on each side are also seen, as well as the means of attachment of the frames to the rear side of the smokebox.



    My last photo is a view looking back along the engine, with the somewhat rusty big end visible on the crank axle.



    I hope that others will find these views helpful, in gaining an understanding of the layout of early valve gears.

    Mike
  24. MikeOxon

    Fortibus es in ero

    By MikeOxon,

    Well, only two buses actually, but the latest one has given me enough trouble for 40! I described building a GWR horse bus from a white metal kit in an earlier post and commented then that an etched brass version might provide better details. I've now tried the etched brass kit from 'Scale Link' but it's not been easy! In fact, decidedly 'trying' at times.
     
    If you suffer from any signs of hamfisted-ness or less than perfect eyesight, do not attempt this kit! By 4mm standards, it is very fiddly and, as I progressed, I felt often needlessly so!
     
    The etch is only about 7.5 thou (0.2 mm) thick and hence, bends very easily. The instructions suggest building the box structure of the body first, which is only held together by a micro-thin strip above the rear door! I found there was no strength in the body, to allow me to either glue or solder the floor-well into place reliably.
     

     
    In the end, I flattened out the body again and soldered the floor-pan to one of the sides and then folded the body around the floor-pan, to solder the opposite side. This worked fairly well. Throughout the construction, however, it is impossible to apply any pressure, when attaching parts, as the structure just collapses. I found this very frustrating on several occasions.

     
    The instructions suggest fitting tiny details, like the lamps (very basic, with no back, bottom, or top) and the handbrake-lever, early on, where they would subsequently be very vulnerable to damage during the rest of the construction. I would say "do not do this!". There are many other places where both the design and instructions leave something to be desired. For example, although there is a very fragile brake lever, there are no brakes on the wheels!
     
    To assist construction, I used Blu-Tack to hold some of the tiny parts together during assembly..This was particularly useful when soldering the axle strip to the notches in the springs on each side of the body.
     

    The use of such a thin fret is a liability in several areas, not just from its lack of strength. For example, the wheels are only a scale 1/2 inch thick, rather than about 2.5 inches for the real coach. The axle itself is just a flat strip, so the wheels do not rotate, despite a complex construction involving two minute washers inside, and a washer and hubcap outside the wheel. The designer apologises for there being no working door handle but I would much rather have seen some etched spring detail, brakes, and ribs on the roof in the correct orientation.
     

    An advantage of etched brass is that some fine details, such as the rails around the roof, can be included but there was no obvious means to connect these at the corners. I left short lengths of the sprues in place, to facilitate connection, but there was still very little attachment area and, in trying to hold these joints together, I inadvertently broke off the rear rail - what was that about ham-fisted!
     
    I'm not even going to attempt fitting the micro-fine strips that are intended to form the beading around the body sides, though I might try sticking them with the paint, later.
     
    So, in summary, a delightfully delicate but somewhat flawed design. I feel that a mix between the rather 'chunky' white metal kit and this 'fragile' etched brass version could have resulted in a very good overall model. Next time, I'll scratch build one!
     

     
    I have another of these kits, to make a 'Victoria' carriage, but I am going to think how to provide a more robust structure, before starting the build, and I'll probably use different wheels.
     
    Good news - I've heard that my Cleminson chassis kits will arrive shortly - apparently, there has been a problem in the sorting office, which delayed my order - so I'll soon be able to put together some coaches, using my laminated sides
     
    Mike
  25. MikeOxon

    From the Stars to Fire Fly

    By MikeOxon,


    General
    It’s been a wet Bank Holiday here and, stuck indoors, I found myself thinking about what it was that made the ‘Fire Fly’ class so special. The following notes reflect my musings:
     
    After all, these engines looked very similar to their immediate predecessors, the ‘Stars’ that the GWR bought from R Stephenson & Co. This similarity is obvious in the first engine photographs ever taken, which include ‘Polar Star’, outside Cheltenham shed in the late 1840s.
     

    ‘Polar Star’ photographed at Cheltenham c.1849
     
    Thee were 12 ‘Stars’, of which ‘North Star’ became famous as the first reliable engine operated by the GWR. Even ‘North Star’ needed some adjustments to its draughting, carried out by Brunel and Gooch before it was able to achieve its true potential.
     

    North Star replica – Steam Museum Swindon
     
    ‘North Star’ and its sister ‘Morning Star’ were bought from stock that had originally been ordered by other railways but were not delivered. They were rather hastily adapted to the Broad Gauge and ‘North Star’ was given 7 foot diameter wheels in an attempt to meet Brunel’s low piston speed requirement. On the other hand, ‘Morning Star’ retained it’s original 6’ 6” driving wheels.
     
    It was typical of the time that only rough sketches were made of the alterations required. As Brian Arman comments in Part 1 of his survey of Broad Gauge engines: “it was probably only intended as a general diagram to demonstrate to the shop floor staff the new frame and axle arrangements … The practical adjustments and decisions by which these changes should be made were left to the skilled shop floor staff” This epitomises the way in which construction proceeded at that time.
     
    In addition, the RCTS ‘Locomotives of the GWR, Part Two’ makes the comment that: “While of the same general design with slotted outside frames these engines differed from each other in detail”. I think that this is a key point, when we compare these engines with the the Fire Fly class, designed by Daniel Gooch.
     
    A Variety of ‘Stars’
     
    To demonstrate how different these ‘hand built’ engines used to be, I looked through all the information about the Stars, provided in Brian Arman’s comprehensive series ‘The Broad Gauge Engines of the Great Western Railway’ [which I strongly recommend] and picked out a little from there to make the following table:
     

    * Polar Star was the first to be fitted with flanged driving wheels
    (?) indicates the engine was stated to be similar to another engine
     
    Note that four years elapsed between the first and the last, and that ‘Fire Fly’ was delivered in March 1840, when only the first four ‘Stars’ had been delivered.
     
    The boilers of Rising Star and Bright Star were 2 feet longer than the earlier engines. Following them, Shooting Star is described as similar to Evening Star, suggesting a reversion following some experimentation. Shooting Star did, however, differ in having a lower top to the firebox casing, with the manhole on the flattened top rather than at the front, as on the other engines.
     
    Did schoolboys of the time vie with each other in recognising individual engines as they passed by on the line?
     
    Many of these engines were re-built before the end of the 1840s and several became 4-2-2T engines. We are very fortunate that E.T. Lane, a pupil at Swindon in the 1840s, who sadly died at the age of 20, made several sketches of Star class engines in their original form. These give a good impression of the amount of variation between some of these engines.
     

    ‘Evening Star’ as sketched by E.T. Lane
    Note the Haycock firebox in place of the round-top of ‘North Star’
     
     

    Rising Star as sketched by E.T. Lane
    Note the lengthened boiler and wheelbase
     
     

    Royal Star drawn by E.T. Lane
    Note the Gothic-style of firebox
     
    As noted above, none of these engines kept its original appearance for long. Compare the following photo of ‘North Star’, taken after its re-building in 1854, with my photo (above) of the replica in the Swindon Museum.
     
     

    North Star photographed at Swindon in 1871
     
    The Gooch Revolution
     
    Daniel Gooch had taken on the role of locomotive superintendent of the GWR, a few days before his 21st birthday. He soon found that he had a very motley collection of locomotives, with which he had to try and run a train service. He was heavily criticised by some members of the GWR Board but had the courage to write a detailed appraisal which, in turn, was highly critical of decisions taken by his boss – Brunel! He won through and absorbed the lessons he learned from struggling to maintain a fleet of engines, within which each member had its own problems and there were no ‘common’ solutions.
     
    He put this knowledge to good use,when he planned ahead to meet the great expansion that was to be needed, once the line was completed through from London to Bristol. He had to order a large number of new engines from several different manufacturers, because no one supplier had the capacity to meet his requirements. In doing this, he introduced the idea that components had to be standardised and he went so far as to provide templates, which each manufacturer had to use in order to ensure commonality.
     
    This was the true revolution that he started with his Fire Fly class – they were a true ‘class’ that could be maintained be means of common adjustment techniques and by drawing from a store of spares that would fit whichever engine needed them. Thus, mechanics who could service one of these engines would have no trouble in dealing with any of the others. This was the start of modern ‘production’, leading eventually towards Henry Ford’s mass production techniques.
     
    His experience had also taught him where the weak points lay and, hence, he paid special attention to these by demanding new processes, such as ‘steeling’ or hardening of surfaces, where wear could be expected in service.
     
    I expect he met some resistance from those staff who were used to ‘doing their own thing’ and several of the engines he received were rejected because his instructions had not been followed. Gooch was tough enough to insist that his requirements had to be met, although he was also ready to accept suggestions for improvements, when these were justified It was by these means that the ‘Fire Fly’ class became the successful engines that they undoubtedly were.
     
    Mike
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