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MikeOxon

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  1. MikeOxon

    North Leigh Creamery

    By MikeOxon,


    general
    It's been a cold, wet, dull, Spring and I have been finding it difficult to gain much inspiration for modelling. I got somewhat bogged down in the intricacies of what Amy Wilcote calls those 'old broad gauge things'. I have, however, been enjoying viewing the splendid work shown by other modellers, in various threads on this site. So, in an attempt to get my own ideas flowing, I have been wandering around some of the less familiar parts of North Leigh.
     
    The creamery is not a very attractive building and that end of the layout rarely features in my photos, so I thought I would poke my camera into a few areas and see if the results would suggest some ideas for improvement. The creamery lies at the end of a short siding, which also serves the cattle dock, between North Leigh station and the terminus of the narrow gauge line from the quarries:
     

     
     
    At the other side of the creamery, to the right, is the reception area, where milk from local farms is brought in for processing. To the left of the creamery, can be seen the engine shed for the narrow gauge line, with its office in a grounded coach body. Behind are the lime kilns, also served by the narrow-gauge railway:
     

     
     
    Of course, I rarely visit North Leigh without finding that Amy is about, with her easel. She told me that the village is unusually quiet, at present, since their father, Sir John Wilcote, has sent her sister Blanche away to finishing school in Switzerland. (how will they cope?) I mentioned the creamery building and she said that she feels it is a real blot on the local landscape and quite out of keeping with the style of the village.
     
    I was, therefore, somewhat surprised when she brought out a painting, apparently made from a window of the Railway Hotel. I was also surprised to see her accompanied by a foreign-looking gentleman, who was standing very close to her easel. She said that one aspect of the building that she did like was its profusion of towers and odd chimneys, which showed well above the old forge. At this, her gentleman friend murmured something about taking her to see the towers of his home town of San Gimignano, where the warm sun would give an added zest to her painting.
     

     
     
    I thought it would be discreet to leave them at this point but it has been very pleasant to spend a little time thinking about what I enjoy in railway modelling. I agree with Mikkel's suggestion that working on a few small scenes can be a great help in keeping up one's spirits, while larger things hover in the background.
     
    Lets hope that the sun will break through soon and give some rather more pleasant evenings, like the one shown below, also taken from the Railway Hotel window:
     

     
     
    Mike
  2. MikeOxon

    Midnight on the Great Western

    By MikeOxon,


    general
    Time flies! Back in August, I wrote about the 'DCC Concepts' oil lamps that I had installed on the platform at North Leigh. Various events have conspired to limit my modelling activities of late, but I have finally got around to wiring up these lamps.
     
    The enamelled copper wires attached to the lamps are extremely fine, so I mounted small printed circuit boards carrying block connectors, onto which I soldered these wires. This proved a rather cruel test of my eyesight since, although I have an illuminated magnifier on my workbench, I couldn't use this underneath the baseboard - I need an Optivisor, or similar! The difficulty I had in seeing these wires can, perhaps, be appreciated from the following photo of one of the boards in place. I left sufficient 'free' wire to allow the lamps to be lifted out of their sockets and laid flat on the platform, for layout cleaning or whenever they might be vulnerable to other modelling activities.
     
     

     
    'DCC Concepts' include a controller with the set of three lamps, and I mounted this circuit board in a small plastic box from 'Maplin', with more block connectors on the outside, to connect to the lamps and power supply. The circuit has outputs for both filament and LED types of lamp, so my next phase will be to provide some lighting inside the station buildings, using the additional outputs.
     

     
     
    Very fine adjustment of the brightness of the lamps can be made with the multi-turn potentiometer on the circuit board. The 'oil lamp glow' is more realistic on the layout than it may appear on the following photograph, showing an overview of North Leigh Platform, with the surrounding scenery bathed in bright moonlight.
     

     
     
    Because of all the distractions that have occupied my time recently, I have made little further progress on modelling No.184. I did, however, mock up the appearance of my planned model and, in the following photo, show my existing 'Stella' model meeting a 'ghost', through the magic of 'Photoshop'. The difference in the proportions of these two types of locomotive is very apparent, with No.184 showing her rather ancient provenance, in the small, low-slung boiler.
     

     
     
    Through a post in the Forums , Geelong1857 drew my attention to the 'E.B.Wilson-style' safety-valve covers, available in 4mm scale from 'RT Models'. I have bought some of these brass castings and am strongly tempted to model the engine in its earlier form, just to make use of these components!
     

     
     
    Finally, a closer shot of North Leigh station, with a late-night branch passenger train just arriving. (The lamp on the locomotive is, alas, simulated using 'Photoshop' ..... for now!)
     

     
     
    Mike
  3. MikeOxon

    Scenes around North Leigh

    By MikeOxon,


    general
    I have written before in this blog about the Wilcote family, whose activities formed such a large part of the social life of North Leigh in the late 19th-century. Any regular readers will know a little about the younger daughter, Blanche, but her sister, Amy, was a far more serious character.
     
    Like any well-educated young lady of the period, Amy enjoyed practising her artistic accomplishments. Remarkably, some of her work has survived and come into my possession, so I am fortunate to be able to show some of her paintings of scenes around the village. She was no 'wishy-washy' water colourist but had clearly studied many of the new works being produced by the major artists of the period, and she attempted to copy their styles.
     

    View from North Leigh Station to the Quarries Beyond
     
    Does that sky indicate that she has, perhaps, seen works by the post-Impressionists? More conventional perhaps, is her study of one of the farms that lie below the steep slope leading up to the quarries:
     

    North Leigh farmhouse
     
    Her subject matter was not, however, confined to 'pretty' cottages and 'scenic' views but included the railway and the machinery associated with it. Indeed, she has been reported as expressing outlandish views, such as wishing to study engineering. History does not record how Sir John responded to such bizarre suggestions!
     

    North Leigh Sawmill
     
    Perhaps her most remarkable achievement is her painting of a local train, headed by one of the Dean 2-4-0s, arriving at the station. it is such a pity that there weren't more artists like her, capturing the colours and atmosphere of the late Victorian railways.
     

    North Leigh Station
     
    I wouldn't like anyone to imagine that I myself have any ability with an artist's paint brush. I was looking at some of the work in the Forum Thread on Railway Art and remembered that I have a computer program called 'Dynamic Auto Painter'. Somehow, the software seems to have encapsulated Amy's spirit and has transformed some of my layout photos into her style!
     
    Mike
  4. MikeOxon

    Track Maintenance

    By MikeOxon,


    general
    Most of my train-running recently has been for the enjoyment of my young grand-children. For this, I tend to use my reliable ‘1854’ saddle tank, with its heavy ‘Wills’ cast body and ‘Hornby’ chassis that make it fairly ‘bomb-proof’
     

     
    Trains at North Leigh
     
    Suddenly, after what has been many months (if not years) of reliable running, the engine de-railed on the three-way point at the West end of North Leigh station. Following application of the ‘big hand in the sky’ breakdown gang, I tried again and exactly the same derailment occurred. It was time for some forensic examination. This activity has delayed any further work to complete my Armstrong Goods – although eagle-eyed readers can spot the unfinished model head-to-head with a Dean Goods in the photo above.
     
    I find that the camera in my iPhone is an excellent tool for photography in awkward places – the problem point is partly inside a tunnel mouth – and the photos revealed that the blades were not closing completely.
     

     
    Damaged 3-way Point
     
    It proved to be a tricky operation to re-shape the blades so that they both closed and provided electrical contact. These points are clearly rather delicate, as the point blades have to be very thin to allow the overlaps necessary for three-way operation. I do not know how the damage happened but can only assume that a wheel flange caught the end of a blade and distorted it.
     
    Troubles rarely come singly and another point, right at the back of the layout, also started ‘playing up’. This is one of the original Hornby-Dublo points that does not have a very positive action and, after several years, it seems that vibration had moved the blades here as well! Industrial action in sympathy with the other point, I expect
     
    Following this disruption to the normally placid life of my railway modelling , I took the opportunity to carry out a general refurbishment and cleaning of all the track-work, especially on the narrow-gauge sections of my railway, which are especially prone to poor electrical contact if the rail-tops are not perfectly clean.
     
    I realise that it is a long time since I’ve shown any photos of the narrow gauge, so took a couple of ‘aerial views’ with my iPhone. I find this is now my preferred ‘camera’ for model photography because its tiny lens and sensor provide great depth of field, even under normal layout lighting.
     

     
    Overview of Farms and Quarries above North Leigh
     
     

    Narrow Gauge activity at the Quarries
     
    I also thought it was time to ask Amy Wilcote if she had been doing any new paintings and she showed me an unusual night-time canvas of North Leigh station, under the glow of oil lamps. I am pleased to share it with you all:
     

     
    North Leigh by Oil Lamps – by Amy Wilcote
     
    Now that the dark evenings are with us, I hope to be able to catch up with some of the modelling that has been ‘on hold’ while carrying out maintenance.
     
    Mike
  5. MikeOxon

    A Tender for No.184 - part 2

    By MikeOxon,


    general
    I realise that I left matters hanging with the tender for No.184, in my post of almost two years ago!
     
    The awful truth is that I rather lost interest, when I found that I had made the frames of the locomotive too wide, so that the outside cranks tended to bind. I simply couldn’t face starting again from scratch until, quite recently, I hit on the idea of simply cutting off the folded edges of the plate which supported these frames and fitting new support members, made from short lengths of Broad-gauge bridge rail. These supports were placed closer together, taking advantage of the ‘narrow gauge’ represented by 00 wheel-spacing.
     

     
    Once I had soldered the frames onto these rails, I found that there was now sufficient clearance for the wheels to rotate freely, when the outside cranks were fitted, so that, in principle, I now have a working engine – once I get around to fitting a motor and gearbox.
     
    The tender was largely complete when I wrote the earlier post. Since then, I have added springs above the footplate, wheel-bearings, and wheels. The paint is Rustoleum Dark Green, which has the bluish tinge required for a Wolverhampton locomotive, with Burnt Umber acrylic on the frames. The grease-type axle-boxes on both the locomotive and the tender are simply small rectangles cut from a length of brass strip. Further additions, still to be applied, are toolboxes and a suitably high coal load – old photos often seem to show a remarkably large mound of coal on these small tenders!
     
    Having made these changes, I decided it was time to wander down to North Leigh and see how it was looking in the evening light. The setting sun was floodlighting the hills near the lime kiln, beyond the buildings of the creamery, while the oil lamps on the platform had already been lit.
     

     
    No.184 was heading the local service from Oxford to Witney, with its train of old coaches, probably dating back to the sixties. On the adjacent track, more modern Dean coaches can be seen, including a clerestory 6-wheeler composite to diagram U29, forming an Oxford-bound train, which was in the charge of Stella class no 3505.
     
    I was not surprised to find Amy Wilcote with her easel near the station. She seemed to feel that I have been neglecting North Leigh and wondered why I was spending so much time “thinking about those old Broad Gauge things”. I assured her that I will aim to spend more time in future, attempting to finish a few of the many projects I started – not to mention Blanche’s dresses 🙂
     
    Mike
  6. MikeOxon

    A Tender for No.184 - part 1

    By MikeOxon,


    general
    It's been a while since my last entry in this blog - lots of summertime activities getting in the way of modelling! I've also had that common modeller's problem of having so many things to do that it's been hard to decide where to start.
     
    I'm afraid that I have, once again, ignored Blanche's petulant pleas for new dresses and got down to the more mundane task of building a tender for No.184. I produced an outline drawing for this tender by starting from a side-on photograph of what appears to be a similar tender behind 0-6-0 No.244
     

     
     
    I then used AutoSketch to trace around the drawing and produce a cutting diagram for my Silhouette 'Portrait' cutter. I have used a diamond dressing tool as a scriber in the Silhouette pen holder, to mark out the cut lines onto brass sheet.
     

     
     
    The result showed that there was some slight movement of the scriber tip during the process and I think, in future, I shall dedicate a pen holder to this purpose and fix the scriber firmly inside the holder, by means of a ring of 'Milliput' putty.
     

     
     
    After marking out, I cut out the components using jewellers snips, before finishing the edges of the frames with a variety of needle files, to produce the curves around the axle guards. For the oval cut-out in the frames, I drilled a 3mm diam. hole and then opened it out to the correct shape by using a round needle file.
     
    Before folding the tender body, I formed the flare at the top of the sides by rolling the brass around a wooden dowel. I then made a number of short cuts into the rolled top, where the sides are folded from the back panel, so that the flare can be continued around the corners.
     

     
     
    The main structure is now complete, although there is a lot of finishing work to be done - axle boxes, etc.......
     

     
     
    Things are now moving again but there are several other projects waiting in the wings. My train of 4-wheelers is in need of a break (sic) van, which I intend to base on the well-known photograph taken at New Milford in 1873 - an earlier version than the V2, for which a kit is available from the BGS, but it's more fun to scratch-build.
     
    Mike
  7. 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
  8. MikeOxon
    Although popular with several European manufacturers, tender-drive has never been well-regarded in UK, possibly because of some rather poor implementations back in the 20th century. Nevertheless, it does have some advantages, when modelling prototypes from the 19th century. Locomotives of that period were generally quite small, with open cabs, and most passenger classes used single drivers until quite late in the century. These characteristics create two problems for the modeller: there is little space, where a motor can be placed out of sight, and single drivers give poor adhesion.
     
    Some time ago, I found that I could place a Tenshodo SPUD power unit within the front bogie of a Tri-ang Dean Single but, if I were tackling the same problem again, I think I would go for a powered tender, even if a little less elegant as a solution. The disadvantages of a powered tender are the lack of 'daylight' under the body and, in some cases, a rather visible power-train. It is also necessary to provide a high coal load to conceal the motor, though I have several prototype photos to show that this is not as unrealistic as sometimes supposed.
     
    When I converted a Mainline Dean Goods to a representation of a 'Stella' 2-4-0, I initially accepted the rather noisy tender drive motor but then began to explore alternatives. Hornby produce the X9105 drive unit (available from suppliers of Hornby spares), which has a smooth-running, 5-pole motor and a reasonably quiet drive train. It also has the 7' 6" + 7' 6" scale wheelbase, used by many types of GWR tender. My first trial with this unit was to see if one could be fitted into the tender provided with the Dapol (ex-Airfix) 'City of Truro' plastic kit. This approach avoided 'butchering' the Mainline tender, while providing a similar outline from more easily manipulated components.
     

     
     
    Fitting the motor proved quite straight-forward. I had to either cut away or file down several protrusions on the inside of the tender side mouldings and also cut away the 'coal'. The rear part of the top and most of the sides could be retained, with a little filing to increase clearances. I then eased the motor unit into the body from below, with some thin black polythene sheet (cut from a waste-bin liner) to hide the top and provide a base for a 'coal' load. I fitted a miniature computer-style power connector to the front of the tender so that it could be used with different locomotives.
     

     
     
    My first application was to the 'City of Truro' kit, in which I replaced the plastic wheels with Gibson extended-axle drivers. Pick-ups on the locomotive were wired to a matching connector, for coupling to the tender. The result was a smooth and quiet running locomotive
     

     
     
    The Dapol tender is not too bad but does have irritations, such as raised panel mouldings that have to be removed with a scalpel, and it represents a later type, with filled-in side-sheets. I found that a white metal kit of a Dean 3,000 gallon tender, with etched coal rails, is available from Scale Link, so my next step was to try and adapt one of these in the same way. Although I had managed to squeeze the Hornby motor into the Dapol plastic body without modification, the protruding metal 'lugs' were too wide for the Scale Link kit. After carefully wrapping the motor itself in plastic sheet, to protect it from swarf, I skimmed off part of the lugs with a rotary cutter on my mini-drill - do not forget to wear eye protection, as swarf does fly about.
     

     
     
    I stuck strips of electrical tape on the inside surfaces of the white-metal sides to prevent any electrical 'shorts' and then assembled the kit around the motor unit. The end result is quite an attractive coal-rail type tender which, because of the weight of the white metal body, does not need traction tyres to perform well.
     

     
     
    I am now working on plans for some more Dean locomotives, which will be powered by these tenders. I am sure that there are several other tender drive units, with different wheel spacings, which could be used for other prototypes. It would be helpful if suppliers could indicate the wheel spacings or, perhaps, others could contribute a list of suitable modern units, to help in adapting these to different models.
     
    Mike
  9. MikeOxon

    A Tale of Two Tenders

    By MikeOxon,


    general
    I have written before in this blog about the convenience of using tender-drive for small 19th century locomotives, especially for 'single wheelers'.
     
    In my earlier post, I described the conversion of two types of tender kit, both of which represented Dean 3000 gallon tenders. Since then, I've read 'GWR Tenders and all that' in drduncan's blog, which, amongst many other useful insights, showed the close similarity between Dean's 2500 gallon and 3000 gallon designs. He also comments on the tender for the Dapol 'City of Truro' kit, writing "But this is rather crude and will need lots of work to get it to an acceptable standard - but I'd love to see examples that people have worked on."
     
    Well, here we go! I have several of these inexpensive Dapol kits and have found them to be a useful 'quarry' of parts for various models. Previously, I built one of the 'City' tenders around a Hornby X9105 drive unit, which has the 7' 6" + 7' 6" scale wheelbase appropriate for the 3000 gallon Dean tender.
     

     
    Dapol 'City of Truro' with motorised tender
     
    I've now realised that the 2500 gallon version would be a better match for many late 19th-century locomotives, including my model of a 'Stella' 2-4-0. So, I decided to see if it would be feasible to modify the Dapol kit to represent this smaller tender. I also needed to find an alternative drive unit, since the requred wheelbase is 6' 6" + 6' 6". Fortunately, Hornby have another unit, the X2024 (intended for 'James the Red Engine') with this wheelbase, so my first step was to buy one of these.
     
    Next, I scanned drawings of the two sizes of tender from my copy of Russell's "A Pictorial Record of Great Western Engines" and overlaid these, to make a careful comparison of their dimensions. I was pleased to find that the lengths of the bodies differed by exactly 2 feet, which is the same as the difference in the overall wheelbases. This indicated that, if I made two cuts between each of the axles, I could end up with both the correct body length and the correct wheelbase!
     
    My method is to do a 'trial run' by means of 'Photoshop' on the computer, before attacking any hardware. The following illustration shows my planned cuts, with the results overlaid, first, over the 2500 gallon tender drawing and then over a scan of the X2024 drive unit.
     

     
     
    This simulation looked OK to me, so I made the necessary cuts in the Dapol sides,using my fine 'Silky' mini-saw, completing the 'cut and shut' job with 'Slaters Mek-Pak'. The next job was to clean up the sides, both to remove the raised lining (so thoughtfully included!) and any roughness at the joins. My favourite tools for this job are small wax-carving chisels, which work extremely well on the rather soft Dapol plastic. I always use the widest chisel possible within the available space, to minimise the possibility of the edges scoring the plastic, although this is hard to avoid completely.
     

     
     
    After 'cleaning up', it is simply a case of building the rest of the kit around the Hornby drive unit. In the past, I have skimmed off part of the lugs on the sides of the drive unit but here I simply 'shimmed' the tender sides at their ends, with fillets of 20 thou plasticard, to achieve a good fit. The result is a tender that is about 0.5mm too wide but, for me, this is acceptable and insignificant against the '00' gauge compromise.
     
    I adapted the lining and lettering that I had already drawn for the 3000 gallon tender and followed my usual method of printing a single sheet to cover the whole side of the tender, which also masks any slight scoring of the plastic. The result makes a very considerable difference to the overall 'balance' of my 'Stella' model, when the two are placed together, as shown below:
     

     
    UPPER - with original 'Mainline' tender
    LOWER - with shortened 'Dapol' tender
     
    There's some final 'tidying up' to do (handrails etc) but I think it's quite a good result, apart from the wheels, perhaps, which are part of the drive unit.
     
    As a footnote, I happened to notice, in the photo of a 'Stella' in 'Great Western Way' (1st ed. p.31) that slates seem to have been set on edge along the sides of the tender, presumably to help secure a large coal load. I may try something similar, to disguise the 'motor hump'.
     
    Mike
  10. MikeOxon
    I've read that some people like blog posts to be fairly substantial, so I'll include a resumé, in this post, of the story so far, before showing photos of my model of GWR No. 184. There are more details in the earlier posts in this series.
     
    Background
     
    I chose this prototype since it was one of the first standard-gauge engines to run on the GWR, following the absorption of the Oxford, Worcester, and Wolverhampton Railway (otherwise known as the 'Old Worse and Worse'). No.184 was one of six engines built by E.B.Wilson in 1853 and this particular engine survived almost until the end of the 19th century, appearing in several photographs that document its re-builds at Wolverhampton Works in 1871 and 1893 It is also the subject of a sketch by C M Doncaster, which shows it at the head of a train of 6-wheelers approaching Reading Station. I decided that I would like to emulate this scene on my model railway.
     
    Method of Construction
     
    The first step was to create some drawings of the engine from a mixture of both photographs and drawings of similar engine types. I used these drawings to construct paper templates, so that I could check clearances, etc. for an 00-gauge model. I then cut out the major components from brass sheet and rolled the boiler by hand. The following photographs illustrate the major stages in the construction, together with dates at which each stage was achieved.
     

     
    Because I was working mainly from paper templates, I made very few dimensioned drawings and fitted together the various parts by 'trial and error'. I often cut out a part from paper, initially, and then, after trimming the paper to provide a close fit, I replicated the component in brass. The major components of the engine body fitted together as shown below. Although I was concerned, in the early stages, that the structure felt rather weak, it all became pretty rigid, once the various sheets were soldered together. I was pleased to find that very little filler was needed, since the boiler and firebox fitted closely around the wheel arches. I used some book-binders' glue (which appears to be a tough form of PVA), to fill any remaining gaps. This proved very effective in providing a resilient seal, rather like bath caulk.
     

     
    Chassis
     
    I built the chassis from a pair of brass strips, soldered together while drilling the holes for the axles and frame spacers. For more details,see part 6 of this series. Initially, the model will be powered by its tender but I have made sure that there is sufficient space for a motor to be fitted inside the boiler.
     
    To achieve this space, I cut away the lower half of the boiler, where it is hidden behind the splashers and the firebox. Top and underside views of the body are shown below:
     

     
    Detailing
     
    I made boiler bands from 5 thou brass sheet, cut into strips and stuck onto the boiler barrel using super glue. I also added rivet detail to the outside frames by using the brass detailing strips supplied by 'Mainly Trains'. These were also fixed with super glue.
     
    I made sandboxes from small wooden blocks, wrapped in 2 thou brass foil, with a separate brass 'lid'. The springs are white metal, mounted above the footplate on nickel-silver wire uprights. Handrails are, similarly, nickel-silver wire (0.5mm). Outside cranks and coupling rods are from 'Alan Gibson'.
     
    Since the main dimensions and appearance of the prototype changed very little throughout its re-builds, I keep in mind the possibility of back-dating my model to an earlier time period. I found that 'RT models' supply 4mm scale brass dome and safety valve cover in the E.B.Wilson style but, for the present, I have installed an 'Alan Gibson' '517-type' brass dome.
     

     
    Painting
     
    I decided to paint my model in a representation of GWR 'Wolverhampton 'livery, which I understand to have been based on the former OW&W livery. The Wolverhampton style of painting differed from Swindon, in that all items above the footplate, including splasher fronts and sand-boxes, were the same colour as the boiler, while the frames below the footplate and the wheels were brown.
     
    My first step in painting, after a thorough clean-up of all the brass-work, was to apply an overall spray of grey primer. Then, for the boiler colour, I chose to use 'Rustoleum Painter's Touch' dark green enamel, which looked a reasonable match to descriptions of the 'blue-green' colour used at Wolverhampton This is a water-soluble paint,with a rather 'plastic' feel that dries to a 'wet look' finish. I found that it brushed more smoothly when thinned with a little water I am fortunate to have inherited some 'Winsor & Newton' series 3A sable brushes, which have superb paint-holding capacity and super-fine tips. They really make hand painting a pleasure! I think the finish will need some matt varnish in due course, since even 19th-century cleaners would find it had to maintain such a gloss!
     
    For the brown frames and wheels, I used 'Winsor & Newton' Burnt Sienna artists' acrylic colour. Again, I thinned the paint from the tube, to produce a smooth brushing consistency with excellent covering power. If any of the 'painting gurus' on this site happen to read this, I should be interested to know why artists' acrylic is rarely mentioned for model painting, since I found it very pleasant to use.
     
    For the black areas (footplate, smokebox, etc.), I used Humbrol black acrylic, which I find dries to a good-looking 'oily' sheen.
     
    Lining and Lettering
    .
    I prepared artwork for the lining and number plate by the methods I have described previously in this blog.
     
    Wolverhampton lining was black and white, so I used white inkjet transfer paper. My copy of 'Great Western Way' (1st.ed.) gives few details, except to state that the white edges of the lining were broader than the equivalent orange edging used at Swindon. Another factor to take into account is that the printed black centre lines tend to spread slightly into the unpainted white edges. I made a few test prints to determine appropriate widths that seemed to match the visual impression seen in old photographs.
     
    I scanned one side of the model to provide 'actual size' templates of the cab sides and sand boxes, on which I 'drew' the lining on the computer screen, as shown below:
     

     
    For the brass fillet between the boiler and smokebox, I cut a sliver of 1 thou brass shim and attached it to the boiler with PVA glue. Cutting this very thin material produced a natural curl, which I exploited to help hold it firmly against the boiler.
     
    The 'Current' Model
     
    I cannot describe the model as 'finished', since there are still many additions and improvements that I wish to make, but it has reached the stage where photographs can give a reasonable impression of what I have been trying to achieve.
     

    My model of GWR No.184 attached to 2500 gal Dean tender (powered)
     
    As I mentioned above, the model is not yet 'self-powered' but can be 'driven' by means of the 2500 gal Dean tender that I described in a previous post.
     
    When seen in isolation, it's not easy to appreciate its small size and rather 'antique' feel, so I have taken a couple of photos to set it in context.
     
    One of my aims, at the outset of this project, was to represent the scene drawn by C M Doncaster. Here is my interpretation, built around some of the models I have built of GWR 6-wheel coaches:
     

     
     
    and here it is alongside Armstrong's 'Queen' class express 2-2-2, the first of which was designed 20 years after No.184 was built:
     

    GWR No.184 alongside 'Queen' class at North Leigh
     
    Conclusion
     
    This was the third model that I have completely 'scratch-built' from brass sheet; the others were the 'Queen'-class 2-2-2 and my interpretation of Dean's 4-2-4T, No.9.
     
    It proved a trickier build than the others, mainly because of the 4-coupled chassis but, also, the raised firebox and the need to leave space inside the structure to add a motor at a later date. My 'Queen' was only ever intended to be tender-powered, while the 4-2-4T is powered by a 'Tenshodo' SPUD in the rear bogie.
     
    Construction took longer than I expected because of many non modelling-related interruptions and I was beginning to get a little impatient towards the end. There are quite a few mistakes that could be corrected in a re-build, especially the shape of the top of the firebox. I've decided, however, to set engine building on one side, for a while, so that I can concentrate on some scenic work, which is badly needed on my layout, if it is ever to represent the sort of 19th-century scene that I have in mind.
     
    If anyone else feels moved to have a go at scratch-building a 19th-century type of locomotive, I would recommend starting with a 2-2-2, since these are very straightforward, with none of the alignment problems associated with coupled engines. I feel that, if you can build a wagon, then a 2-2-2 engine is not that different! Also, I have found that brass sheet is an easy material to use – in some ways easier than plastic card, because it can be folded and rolled into curved shapes. Once you've cut your teeth on a simple prototype, you can follow whatever course catches your imagination.
     
    I also realise how much I have learned, and absorbed, from various books, and should mention, in particular, Iain Rice's “Etched Loco Construction”, which helped me over many hurdles.
     
    Mike
  11. MikeOxon
    Although this may seem a short post, it represents a very big step for me! I had been seriously concerned that I would not be able to construct a chassis with sufficiently well-aligned axles, within the constraints of my own abilities and my lack of any real workshop facilities - just a desk and Dremel drill on a stand.
     

     
    My work-desk
     
    When one builds a kit, the designer has already made lots of difficult decisions for you. A scratch-builder has to think out every little step for himself - what metal to use for the frames, where to position the spacers, and so on. I decided to cut my frames from 1mm x 6mm brass strip and to hold them apart by three Markits-type spacers. Since one of the driving axles is close to the centre point of the frames, I had to decide where to place the 'middle' spacer. I chose to put it ahead of both driving axles, in case the space between them was needed for motor mounting purposes.
     
    Next decision was how to align the frames for drilling the axle and spacer-mounting holes. I have read the suggestion to solder the two frames together, so decided to follow this approach. My iron is a fairly basic Maplin 'solder-station' and, by trial and error, I have discovered that a temperature setting of 285°C works well for me, when using lead-free solder, without too rapid tip-oxidation while 'standing -by'. I've no idea how accurate the temperature read-out is, so other irons may differ. There are convenient buttons on the controller, to switch to pre-set temperatures, and I usually switch to 200°C if I'm not using the iron for a reasonable period. This keeps it warm between uses, without much oxidation. I clamped the frames together, applied some phosphoric acid flux to the ends, and soldered them together. This was fine for holding them when drilling the 2mm pilot holes but, when it came to opening out the axle holes to full size (1/8"), the drill tended to push the frames apart a little, so perhaps I should have soldered them together all along their length. I wasn't sure that my iron had the 'beef' for that and whether I would get them apart again!
     
    I measured the positions as accurately as I could with a metal rule (marked in 1/2mm graduations), scribed guidelines with a small diamond scriber, and then centre-punched the holes for drilling. I used a 2mm drill in my Dremel mini-drill, mounted on its vertical stand. I aligned the drill by eye and held the parts in position with BlueTac and adhesive tape - supplemented by my fingers. Eye protectoirs are essential, since tiny specks of brass do fly about when drilling. I applied a drop of very light oil, which seemed to help the drill to go through quickly and cleanly. Once all the holes were completed and I had checked that they all seemed to be in the right places, I applied the soldering iron again, to separate the two frames. Then I cleaned up all the faces with needle files.
     

     
     
    The spacers screwed in easily and seemed to be well-aligned (I have yet to counter-sink for the screw-heads) but I knew that the acid test would come when it came to fitting the axles through their bearings. I had to use a larger power-drill to open out the axle holes to 3.5mm and then I used a circular needle file to open out the holes very carefully, until the bearings were a firm push fit (with pliers). I smoothed off the ends of the (Alan Gibson) axles and gentle tapped them into the bearings. Everything worked --- they slid into position smoothly between the frames. To say I was relieved would be a great understatement. Actually, I was b----y amazed
     
    With that hurdle crossed, I can turn my attention back to the 'body' and , in particular, to obtaining the various fittings that need to be added. One very prominent fitting on many of these early engines can be seen just behind the chimney. I remember, many years ago, that I found it quite difficult to identify this item, so I'm happy to pass on that it is a displacement lubricator for the cylinders. It was placed in that position for ready access to a steam supply but later, the fitting moved to the sides of the smokebox. Later still, these lubricators were controlled from the cab and led to another fitting that puzzles some visitors to GWR footplates. There is an item in the roof that looks rather like an electric cooker element but it is not there for crew comfort - it is the condenser for the displacement lubricator in these early 20th-century engines.
     
    Mike
     
    Continue to next part
  12. MikeOxon
    I feel it is time for an update on progress with my model of GWR No.184. After a rather static period, when I did little actual modelling but thought quite a lot about the details of this engine, I have at last been cutting metal.
     
    In fact, apart from the fact that it is now made of brass, I have made few changes to my initial paper template. My method of construction followed that used on my first scratch-built model (GWR 'Queen'-class - described in Railway Modeller July 2014). In summary, I cut out the components from scale paper drawings and stuck these (using a glue stick) to 10 thou (0.25 mm) brass sheet.
     
    One simplification that I made, following experience with 'Queen' was not to make a double-fold in the main chassis in order to mount the splasher fronts, but instead to provide tabs on the splashers 'module', to fold under the chassis sides. The main components that make up the body look like this:
     

     
     
    As before, I had little difficulty with rolling the boiler, although I suspect that it helped to have a paper layer stuck to the outside of the brass sheet while rolling. This seemed to help with the smoothness of the curvature and also protected the surface of the brass from scratching. Since the prototype boiler had a diameter of 4' 2", I calculated the scale circumference (3.142 x diameter) and then cut out a rectangle of brass, to roll into a cylinder. I made this tube the full length of firebox + boiler + smokebox, to provide a rigid structure and then added the raised firebox and smokebox as simple wrappers. The stages in assembly are shown below:
     
     

     
    I used a diamond slitting disk on my mini-drill to open up the apertures for the wheels in the floor plate. For the photograph, I've just rested a chimney and safety-valve cover in place, to make it look a bit like a locomotive (!) and have not bought a dome yet - probably a 517-type. The next step will be to fit 'cosmetic' outside frames with embossed rivet detail and then use thin (5 thou - 0.125 mm) brass sheet, to form the curved running plates between the outside frames and the splasher fronts.
     
    Anyone who read my last post on this engine might remember that I had planned to begin with the chassis but, in the end, I decided to repeat the part that was already familiar, having done a very similar body for 'Queen'. I may produce a simple rolling chassis that can be pushed along by my 2,500 gal. motorised tender. I find that tackling a job in easy stages helps to keep up motivation, when I see the outline of an engine start to appear, and allows me to consider different options as I start to add the details.
     
    So far, the outlay on brass sheet has been minimal but costs start to rise once all the detailing components are added, especially wheels, gearbox, and motor. At this stage, I feel that there is a reasonable chance of producing a model that will have at least a passing resemblance to its prototype.
     

     
    GWR No.184 in 'Wolverhampton' livery
     
    As an aside, I have mentioned before that many interesting old books can be downloaded from the Internet Archive website. I recently found that Ahrons' classic 'The British Steam Railway Locomotive 1825 - 1925' can be downloaded and, although I have a facsimile copy, it is useful to be able to copy drawings directly from the digital version. Another interesting find was Sekon's 'The Evolution of the Steam Locomotive 1803 - 1898', which has lots of fascinating detail about many very early engines, and many anecdotes about events during their trials and early use.
     
    Mike
     
    Continue to next part
  13. MikeOxon
    Part 4 already, and I've not actually touched any metal yet! My thanks to all who have given encouragement by their 'Likes' and a warning not to expect any 'model engineering' in this thread - it's more like cut-out scrap-booking - but I enjoy it and it might lead to a working model.
     
    Since my last post, I've re-visited the cab area, so that it can accommodate the rear pair of drivers. On my paper model, I've cut slots in the front of the cab and floor, to allow for the 14.4mm back-to-back separation of 00-gauge wheels. It seems reasonably firm and I can build up the wheel-boxes inside the cab, in the final model.
     

     
     
    The following early view of the footplate of a Dean 2-4-0 shows the 'look' that I wish to achieve, with its very simple backplate.
     

     
     
    A more tricky problem is posed by the boiler. It was easy enough to roll a tube of paper to the correct dimensions. After a few trials, I decided to make the tube extend the entire length from the front of the smokebox to the cab. Photographs of the real engine indicate that, although the top of the firebox casing is raised, the sides are flush with the boiler cladding, so I could add the firebox as a 'wrapper', fixed to the sides of the boiler. I'll leave the problem of creating the shaped fillet needed between the firebox and the top of the boiler for later. The immediate problems begin, when trying to fit the boiler assembly between the wheels.
     

     
     
    As I discovered when building my 'Queen' model, the real boiler diameter scales to something larger than the 00-gauge back-to-back dimension, so some cut-outs are essential. This proposed model raises the additional problem of how to accommodate a motor and drive unit. For this, I turned to the 'High Level' website , from where you can download a very useful 'Planning Sheet', with scale drawings of motors and gearboxes.
     
    By copying the relevant drawings and pasting them over my own scale drawings of the engine, It appears that I should be able to accommodate a 'RoadRunner' gearbox with 'Mashima 1220' motor, within the profile of my model. I've also indicated how it should fit within my paper template
     

     
     
    My plan is to cut away the underside of the boiler, where it will be hidden behind the wheelarches and firebox sides, sufficiently to allow the superstructure to be lowered over the motorised chassis. I have not scratch-built a working chassis before, so intend to keep it as simple as possible. I shall use my kit-built model of a Hudswell-Clarke 0-4-0 (TVR 'S'-class) as a basis for the design.
     

     
     
    The kit chassis consists of two brass strips, separated by Markits-type spacers. Providing that I can manage to drill the holes in the right places, it does not look too difficult, though when I look at Snitzl Works amazing Wheel Quartering Jigs , I wonder if I might be fooling myself.
     
    I feel that I had better turn my attention to trying to build a working 0-4-0 chassis, before I do any more on superstructure design
     
    Mike
     
    Continue to next part
  14. MikeOxon
    I've re-titled this thread, so that it doesn't read as though I'm building a whole fleet of engines - one at a time is enough for me!
     
    My first attempt at scratch building was a 'Queen'-class 2-2-2. I chose it on the grounds of simplicity, since building an uncoupled 2-2-2 is little different from building a wagon. My first step was to draw the constituent parts and then cut these out as a series of paper templates, so that I could check the fit of the parts and explore different assembly techniques, before committing to cutting any metal. I described the approach in more detail in my article 'Simply Victorian', in Railway Modeller, July 2014.
     
    The 'Queen' (or 'Sir Alexander') model did,indeed prove very straightforward to construct,being little more than a cylindrical tube for the boiler over a folded flat plate for a 'chassis'. The cab was a simple folded brass sheet sat on the chassis behind the boiler and the flush firebox and smokebox were 'wrappers' around the boiler.
     

     
     
    It was natural then for me to start No.184 by copying the same methods. Previous posts described how I managed to produce some reasonable line drawings from available photographs. So, as before, I copied segments of these drawings to represent the outside frames and other main component of my proposed model. I then printed these drawings on a sheet of ordinary file paper.
     

     
     
    I cut out the individual components with scissors and a scalpel, and then stuck the parts together, using PVA adhesive. I find that hair grips are an indispensable aid to assembling paper models like this.
     

     
     
    Now that I can visualise the 3D assembly, I can start to explore ideas on how they might fit together in a metal model. It soon became apparent that a model of No.184 will raise a number of difficulties that were not present in 'Queen'. The coupled wheels are an obvious complication but there is also the fact that these wheels intrude into the cab, which means that this can no longer be seen as a completely separate component, simply 'plonked' on the chassis at the end of construction!
     

     
     
    Instead, I shall look at a means of construction where the cab will be integral with the rear-wheel splashers. The compromises associated with the 'narrow' 00-gauge also come into play, since these mean that the intrusion of the wheels into the cab will be much greater than in the prototype. The backhead will need to be modified, to accommodate the narrow wheel spacing.
     
    On my 'Queen' model, the outside axle boxes were all dummies and, from some angles, the large gaps between these and the 00-gauge wheels were all too obvious. The new engine will require extended axles for the coupled drivers and outside cranks so, hopefully, these will hide the discrepancy to some extent.
     
    I've not started to plan the superstructure yet but it is clear that the boiler will be a more complex construction than 'Queen', mainly because of the raised firebox, which will have to be a separate component. Since I am also hoping to include a motor and gearbox in this engine, rather than in the tender, as before, I shall have to think about clearances for housing these components, especially as I want to keep the footplate clear of any further intrusions!
     
    So, I have a lot more templating to do before I can be sure that I have a viable plan - that is a subject for future posts.
     
    I recently bought a book on the OW&WR (Jenkins, OW&WR Through Time, Amberley 2013 ) and, while the title is somewhat misleading, as it is really about the Cotswold Line to Hereford, it contains several photographs appropriate to my area, including an excellent one of a 182-class locomotive (OW&W 21-class), in original condition, at Evesham Station in 1863. This is especially useful, since it shows the back of the tender that I had not seen in other photos.
     
    I have another book in the same series about the Fairford Branch (Jenkins, The Witney & Fairford Branch Through Time, Amberley 2013 ) and this includes useful information about the planned lines around Witney. From this book, I learned that the route via North Leigh (the subject of my own layout) arose as part of a spate of schemes during the 1840s, including the `Oxford, Witney, Cheltenham & Gloucester Independent Railway', which obtained an Act of Parliament for the construction of a `mixed ­ gauge' line. In the parallel universe inhabited by my layout, where all this came to pass, it is now clear that the wide spacing of the tracks through North Leigh station is the result of this broad gauge heritage.
     

     
     
    Mike
     
    Continue to next part
  15. MikeOxon

    GWR ‘Sir Daniel’

    By MikeOxon,


    general
    A comment on my recent post about modelling Rocket reminded me that my first scratch-built locomotive was an Armstrong 2-2-2 that I constructed 10 years ago and described in ‘Railway Modeller’, July 2014 , as ‘Simply Victorian’. I explained in that article that I was encouraged by a drawing of one of these engines in Russell’s ‘A Pictorial Record of Great Western Engines’ with the caption comment that: "The utter simplicity of these early engines can be seen." The idea of ‘simplicity’ appealed to me!
     
    Later, when contemplating additional engines for my ‘North Leigh’ layout, I considered other Armstrong types, including the earlier ‘Sir Daniel’ class. At that time, I wrote of my first model that “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! It was 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.”
     

    Principal Components of my 1st model
     
    Whereas the 'Queen / Sir Alexander' class that I chose to model were the last engines designed by Joseph Armstrong before his untimely death in 1877, the 'Sir Daniels' were his first standard-gauge engines built at Swindon, starting in 1866,
     
    Writing in 2015, I decided that “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”
     
    I felt at that time that my options were limited by what I could make using the traditional methods of brass-sheet construction. Since then however, my horizons have widened considerably following my adoption of 3D printing which greatly eases the problems associated with matters such as open splashers and other awkward features.
     

    Sir Daniel No.378 in ‘as-built’ condition
     
    One elephant remains in the room, however, and that is the fact that a ‘00’ gauge model really is a ‘narrow gauge’ model, within which true-to-scale boilers may not fit! In the case of my ‘Queen’ model that meant taking jewellers’ snips to the brass sheet I intended to roll into a boiler – fortunately, it still rolled successfully! It also meant that I had to adopt covered-in splashers to hide the gaping hole that I had created, so my model had to be of the later Dean rebuild of the type.
     
    Now, with 3D printing, I felt able to look back to the original design of 1866 for an engine that would be significantly ‘different’ from a rebuilt ‘Queen’ prototype of 30 years later. I still had to take into account the constraints of ‘00’ gauge, with a back-to-back dimension between the driving wheels of only 14.4 mm (3’ 7” at prototype size) against a boiler diameter of 4’ 2” (plus cladding).
     
    According to RCTS ‘Locomotives of the GWR’,Part 4, the main dimension of interest to a modeller were:
     
    ‘Sir Daniel’
    Cylinders. Diam. 17" Stroke 24" Boiler. Barrel 11’ 0" Diam. outs 4' 2" Pitch 6' 11". Firebox. Length outs 5' 4" Wheels. Carrying 4' 0". Driving 7' 0" Wheelbase 7' 8" + 8' 4", total 16' 0".  
    For comparison, the later ‘Queen’ class had shorter boilers but larger fireboxes and a longer wheelbase of 17’ 6”.
     
    Creating a Model.
     
    I started by considering the design of the boiler and the need to accommodate ‘narrow gauge’ driving wheels. My references were the photograph of ‘Sir Daniel’ as originally built, shown above, and a drawing by Jim Champ, which I imported as a canvas into ‘Fusion 360’
     
    Usually, I like to make the boiler from a brass tube and add a 3D printed cladding, as on the prototype. In this case, however, I had to accommodate the driving wheels, so I decided to 3D print the boiler itself and add weight by lead strips afterwards.
     
    After some thought, I decided on the following procedure:
     
    1. create a cylinder of length 44mm and diameter 18mm, to represent the external dimensions of the boiler plus its cladding
     
    2. create a pair of 28mm diameter driving wheels, with additional 0,5 mm flanges, and mount these either side of the boiler at the ‘00’ back-to-back separation of 14.4 mm
     
    3. Assemble these parts into their correct locations within Fusion 360 to create a visual impression of what modifications would be required to the boiler model, as shown below..
     

    Tackling the 00 gauge Boiler Problem
     
    I realised that the diameter of the cut-outs in the sides of the boiler would have to be wider than this, because it would simplify the design of the splashers, if I could also recess these into the sides of the boiler. I drew a circle of the required diameter in Fusion 360 and then used the ‘extrude’ tool in ‘cut’ mode to create recesses of the depth required to accommodate the driving wheels.
     

    Cutting recesses for driving wheels and splashers
     
    After dealing with that problem, the rest of the construction followed a familiar course. I extruded a pair of outside frames from the drawing canvas and set these at a ‘true scale’ distance apart. This means, of course, that the driving wheels are inset, relative to the prototype, but the overall arrangement of the locomotive is correct. If I wanted to run the engine on scale track, this would be possible, simply by extending the driving axles. At this stage, the frames are purely ‘cosmetic’ and I shall consider the design of the real chassis later.
     
    All the other parts were similarly extruded from the drawing or, for the dome and safety valve covers, I used the ‘revolve’ tool on a profile sketch.
     
    One thing I always have to bear in mind is the ‘printability’ of a 3D model created in Fusion 360. I aim to divide up the component parts, so that each one has a flat surface to lie on the printer bed, from which the rest of the structure can be ‘grown’, For example, I provide flat plinths on the boiler, so that the various boiler fittings can be printed from flat bases. The ‘exploded’ view below shows the collection of parts that can be printed individually.
     

    Components shown separately in Fusion 360
     
    As usual, I also like to do a ‘test fit’ of all the components by assembling them within Fusion 360 as a final check before printing – they can be seen against the ‘canvases’ from which the parts were extruded below:
     

    My model of ‘Sir Daniel’ assembled within Fusion 360
     
    The next stage will be to design a chassis, which will be based on an inside-frame for the wheels. As in the case of my existing ‘Queen’ model, I intend this one to be driven from a powered tender.
     
    Mike
  16. MikeOxon

    What big wheels you’ve got!

    By MikeOxon,


    General
    I reached something of an impasse at the end of my previous entry in this blog. Lots of problems to be addressed but no clear routes to solutions.
     
    Possibly the most striking feature of the ‘Waverley’ class 4-4-0s was their wholly-exposed coupled driving wheels. I therefore felt strongly that this was an aspect that my model had to capture. Unfortunately, there seems to be no commercial source of 24 spoke, 7 foot-diameter driving wheels and, while I fantasised a little about building my own, I quickly realised that it was beyond my skills and the tools that I have available.
     
    Then, looking at my Tri-ang ‘Lord of the Isles’ model, I suddenly realised that its driving wheels had the requisite 24 spokes! For once, however, Tri-ang had not made their driving wheels grossly under-size but they did have massive tyres and flanges, which offered scope for turning them down to somewhere near 7 feet. So, the next step was to buy some spare wheels (Hornby X275/X276) for only £1.90 a pair.
     
    Not having a lathe, I mounted the wheels onto a spindle and fitted them in the chuck of my stand-mounted Dremel drill. I then used a variety of tools, including a diamond slitting disk fitted in another mini-drill, and an assortment of files, to reduce the size of the massive flanges. Even with a minimal flange, the overall diameter (including flanges) was still 30 mm, so I decided to remove the flanges altogether from the leading pair of drivers. With a long, rigid wheelbase, I felt that this would give the locomotive some chance of negotiating curves.
     

     
     
    Another important reason for reducing the overall wheel diameter is that the coupled wheels are mounted very close together, so any excess size increases the minimum possible wheelbase, which I felt would be even more obvious than over-size wheels. After completely removing one set of flanges, I found that I could use a wheelbase of 31 mm, which I was prepared to accept as close enough in scale to the prototype’s 7’ 5”.
     
    Nevertheless, this compromise meant that I had to redesign the inside frames, so as to provide extra clearance between the driving wheels. Since I had drawn the original frames with the Silhouette Studio software, it was easy to modify the details, without having to do a complete re-design. I feel that the revised frames do not ‘look’ appreciably different from the original frames shown in my previous post.
     

     
     
    I ‘tacked’ the frames temporarily to the boiler assembly by means of Uhu adhesive and then checked that all the wheels could be fitted, without fouling each other. Now my model was beginning to look like a Broad Gauge locomotive.
     

     
     
    I assessed the appearance from different angles and believe that it has captured much of the ‘character’ of the prototype, even though it is not a strictly accurate model
     

     
     
    Finally, I set the part-finished model head-to-head with my model of the ‘Rover’ class 4-2-2. This comparison revealed that I need to make further adjustments to the boiler pitch and the frame height but, since nothing is fixed as yet, this will be easy to rectify.
     

     
     
    Of course, I’m not completely out of the woods, yet. There is still the matter of those bicycle-like splashers, with their brass facings.
     
    Even so, I am very pleased to have reached the current stage, which at one time seemed an impossible task for me. I find it rather inspiring to see this mid-19th century locomotive coming to reality on my work bench.
     
    Mike
  17. MikeOxon

    25 years later - ‘Rocket’

    By MikeOxon,


    general
    Having gone right back to 1804 with Trevithick’s locomotives, I decided to start moving forward again - to Stephenson’s famous ‘Rocket’, which was to put passenger-carrying railways firmly on the map.
     
    When I built my Trevithick model, I wanted to put it alongside a model of ‘Rocket’ to illustrate the progress made over 25 years but, although I know I have a 4 mm scale model built from an Airfix kit, ‘somewhere’, I couldn’t find it!
     
    I did find however that there is a 3D printable model of ‘Rocket’ on the same Printables website, where I had found the Trevithick 3D model files. Again, the ‘Rocket’ model was designed for a larger scale than my usual 4 mm/foot but, in this case, the scaling factor needed was not so great.
     
    The model I downloaded was by Václav Krmela, who has made his .stl files available under the Creative Commons (4.0 International License) Attribution-NonCommercial   His model was designed for 1:32 scale, so needed reduction by 42% to print at 4 mm/foot.
     
    Most of the parts printed satisfactorily at the smaller scale but, as with the Trevithick model, I had to thicken the walls of the boiler and chimney to make them sufficient robust. I particularly liked the way in which the design incorporated location tabs, which made it very easy to assemble the printed parts in their correct orientations. For example. I show the basic chassis which has tabs to locate with both the firebox and boiler:
     

    Components of Václav Krmela’s model, showing helpful tabs
     
    These tabs worked perfectly well on my reduced-size prints and are a feature I must aim to include in my own future models.
     
    A feature I didn’t like was that the cross-heads on both sides of the engine were fixed in the same position, so didn’t allow for ‘quartering’ of the driving wheels. When I imported the relevant .stl files into ‘Fusion 360’, however, and converted the mesh bodies into ‘base features’, I found that they split into two parts – the piston body and the piston rod and slide bar – so I was able to re-position the cross heads to appropriate positions along the slide bars. This was unexpected and a feature that must have been ‘lost’ when the .stl files were created!  I have found that the ability to import .stl meshes and convert them to ‘base features’ in ‘Fusion 360’ is very useful, as it allows modifications to be made to downloaded model files.
     
     

    Bodies created in Fusion 360 from original .stl file
     
    To check the overall assembly, I brought all the parts together within ‘Fusion 360’, as shown below.
     
     

    Vaclav Krmela’s mesh model, assembled in ‘Fusion 360’
     
    So now, all I had to do was print the parts. I printed some of the smaller parts in groups, including a set of wheels and a set of various small pipes, rods, and stays. The latter group was on the borderline of what is possible at my chosen scale and I made several attempts before I managed to print a reasonably ‘clean’ set. These tiny parts only took 1 minute to print but adhesion to the print bed was rather ‘hit and miss’ until I tried applying some ‘Pritt Stick’, which increased the success rate considerably – here’s a set, as printed, warts and all:
     

    3D printed pipes, rods, and stays, before fettling
     
    I attached these fragile parts by applying a touch of a 200° soldering iron tip  while holding the ends in place with fine tweezers.
     
    It has been an interesting print job although, looking at the assembled model, the pipework in particular is rudimentary, when compared with the full-size replica. A very significant omission is the pair of pipes carrying exhaust steam from the cylinders to the base of the chimney – this use of the exhaust blast to ‘draw’ the fire was an important factor in the success of Rocket at the Rainhill trials.
     

    Full-size Rocket replica at Tyseley, 25 June 2011
     
    I felt I had to rectify this omission, so I made 3D prints of the two upper pipes and the pipe at the bottom of the firebox. Again I used ‘Pritt Stick’ to ensure that these tiny parts didn’t wander on the printer bed.
     

    My additional 3D-printed pipework
     
    Printing this model has served my purpose in providing a comparison to the Trevithick model, so demonstrating the progress made over the intervening years. The appearance of the ‘Rocket’ model does suffer, though, from the ‘Tri-ang’-like profile to the wheels!
     
     

    3D prints of the downloaded Trevithick and Rocket models
     
    Whereas Trevithick conceived his engine as a ‘general purpose’ machine, ‘Rocket’ was built to meet the very specific requirements laid down for the Rainhill Trials. In particular, ‘Rocket’ was designed to haul light loads at high speed and Stephenson realised that, for this task, adhesion weight would not be a critical factor.
     
    Nevertheless ‘Rocket’ needed improvement for general service use, so there were further rapid developments by the Stephenson company. The next step was the ‘Planet’ class 2-2-0, which introduced the use of a pair of inside cylinders under the smokebox, an enduring feature of British locomotives. ‘Planet’ was followed by the ‘Patentee’ in 1833, which established the 2-2-2 as the archetypal British express engine and could be described as the first ‘modern’ locomotive.
     
    A detailed description of Stephenson’s ‘Patentee’ Locomotive Engine was published by John Weale in 1838 “by the liberality of Robert Stephenson, Esq., having been written under his direction and revision by Mr W.P. Marshall”
     

    Stephenson’s ‘Patentee’
     
    My model of the broad gauge ‘missing link’ is an example of this type of engine, which set the pattern for express engines until increasing size and weight dictated the use of more carrying wheels.
     
    Mike
     
  18. 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
  19. 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
  20. MikeOxon

    A Matter of Colour

    By MikeOxon,


    General
    I’m currently pondering what colour I should use for the body of my Broad Gauge ‘Rob Roy’.  References to the colour originally used on Broad Engines declare it to have been ‘Holly Green’ but opinions differ on what shade that name represents.
     
    According to Christopher Awdry’s book: ‘Brunel’s Broad Gauge Railway’, the Boiler Cladding was ‘Holly Green (Dark Blue/Green)’ until 1881, after which ‘Chrome Green’ was adopted. (he quotes the Broad Gauge Society as the source of this information).  It interests me to observe that the ‘GWR Wolverhampton Green’ is also frequently described as a ‘blue/green’ hue, so might the original Broad Gauge colour have been more akin to this Wolverhampton colour than we now realise?
     
    I found some support for this view from an unexpected source. The ‘new’ Great Western railway franchise adopted a new corporate livery in 2015, which is claimed to have been based on the original Broad Gauge engine colour - see https://www.pentagram.com/work/great-western-railway-1/story for more information. I quote: "A bespoke paint has been created for train liveries based on the original ‘dark holly green’ used on the first GWR locomotives." What the sources for the chosen colour were is not revealed but it seems very unlikely that the present colour has anything to do with the original Victorian pigments. The ‘new’ GWR colour is defined in the Wikipedia UK Railways/Colours list as #0a493e, which can also de defined as RGB= 10, 73, 62 or HSL= 170°, 86%, 29%
     
    When I place this colour against the GWR Chrome Green colour described on the GWR Modelling website the result is somewhat startling. Were early GWR engines really this blue?
     

     
    One point to consider is the effect of ‘brightness’ on the perceived hue. As I explain on my website about colour perception , the human concept of colour can be divided into ‘colour’ and ‘brightness’ (or ‘luminosity’). If we maintain a constant ‘colour’ but vary the brightness, perception of the colour can vary considerably, as shown below:
     

     
    To my eyes, at least, the colour does appear more definitely ‘green’ as the luminosity decreases and all the reports of early engine colours agree that they were darker than the later chrome green.
     
    Another colour to consider is the modern interpretation of ‘Holly Green’, described as British Standard BS 4800 14 C 39 - Holly green / Hollybush / #435d50 Hex Colour Code. (RGB= 26, 36, 31). The ‘Encycolorpedia’ website also shows the effect of variations, as shown below, which confirms that darker colours tend to look more green.
     

     
    Finally, I went out into my garden, where there is a real Holly tree, and photographed some leaves, together with seasonal berries.
     

     
    These leaves have a greater green content than the various ‘official’ colours and I find their colour rather pleasing.  I thought I’d see what this colour looks like when applied (by Photoshop) to my (still unfinished) model:
     

     
    In the end, I shall probably look along the array of ‘rattle cans’ in the local motorists shop and make a personal choice, relying on the fact that no-one will be able to contradict me with any confidence.
     
    Mike
     
  21. MikeOxon
    I’ve now managed to produce a set of ‘printable’ parts from the original download from the ‘Printables’ website described in my previous post.
     
    I’m still puzzled by the theories on exactly which of Trevithick’s locomotive engines was actually used for the Penydarren trial, which was the moment in history that put the steam locomotive on the map.
     
    There is a print in the Science Museum collection, said to be the Penydarren engine but it has been discredited because, according to the attached scale, it shown an engine on a 3-foot gauge track.
     

     
    When I compared this print with the illustration in Francis Trevithick’s book, however, it was obvious that they were extremely similar, although the book states that gauge was 4’ 4”. On further inspection, I realised that the Science Museum print became a very good match (not identical but very similar), if I increased the scale of the print to correspond with a 4’ 4” gauge. Can it really be the case that subsequent authors have been misled by the scale appended to the drawing? I’ve seen so many examples of a wrong scale on a drawing to feel that it is not that unlikely an occurrence!
     
    Incidentally Francis Trevithick, son of Richard, was himself a railway engineer, having been appointed Locomotive Superintendent to the Grand Junction Railway at Edge Hill, Liverpool, in 1841. I mention this to show that he was very knowledgeable about engines
     
    Printing my model parts
     
    Making the parts downloaded from the ‘Printables’ website printable at the smaller scale of 4mm/ft did not prove to be too arduous.
     
    I made all the gear wheels a little thicker by a simple scale change in the ‘Cura’ software. The boiler and chimney were both too thin-walled to print, so I created new versions as simple cylinders in ‘Fusion 360’. The triangular front support for the piston-rod was also too fragile, so I re-drew a stronger version. After assembling all the parts together, I made a ‘rendered’ view of the model within ‘Fusion 360’. The piston-rod and slide bars are indicated as brass rods, which is how I intended to create them for the physical model.
     

    Model of Trevithick’s engine rendered in Fusion 360
     
    Apart from these rods, I transferred all the revised files from ‘Fusion 360’ to the ‘Cura’ slicer program and thence to my printer. In the case of small parts, which take only a few minutes to print, I collected several items together as a single ‘print job’. For example, all the gear wheels were printed together in the printer build plate.
     

    Various wheels and gears printed together – on my printer bed
     
    A curious observation was that, in a couple of cases, small parts which did not print cleanly the first time, gave a far better result when I immediately repeated the print, over the same location on the printer bed (i.e. no change to any of the print parameters). Could the fact that the print head was still warm have resulted in a cleaner start to the re-print?
     
    Assembling my model
     
    When I first viewed the collection of tiny parts that I had printed, I quailed at the thought of ever being able to connect them all together! Fortunately, I have a good illuminated magnifier and, very importantly, have recently had cataract surgery that has restored my acuity of vision!  I’m also pleased to have found that my hands are still steady enough to thread small-diameter rods through barely visible holes in tiny parts!!!
     
    Of course all you 2mm FS modellers will wonder what I’m talking about but it was a delicate-seeming operation for me to attempt. I don’t know if Julia Adams still visits this site but it was seeing her demonstrations at various shows that assured me that such fine work is possible.
     
    So, where to begin?
     
    I decided to try threading the main drive-shaft through the lugs on the boiler end-plate, to connect to the flywheel on one side and the primary gear wheel on the other. It turned out that a 1 mm diameter brass rod slid through the lugs, after just a slight touch with a reamer, so I soon had these parts joined together:
     

    My Primary Driveshaft Assembly
     
    I realised that there is a boiler extension below the drive shaft, which may explain why the boiler length is described in the references as being 6 feet. This extension presumably accommodated the curved end of the return flue inside the boiler.
     
    This initial step demonstrated that there was a good chance that other shafts and gears would all fit together so, with a little more confidence, I assembled the main driving wheels onto their 2mm diameter steel axles. In the prototype, the axles were fitted to a very basic wooden ‘boiler truck’, to support the main components of the engine. This illustrates the concept that Trevithick had of designing his engines as ‘multi purpose’ machines. In a letter to Mr. Giddy dated February 22nd 1804, Trevithick wrote “An engine is ordered for the West India Docks, to travel itself from ship to ship, to unload and to take up the goods to the upper floors of the storehouses by the crane, and in case of fire to force water on the storehouses. The fire is to be kept constantly burning in the engine, so as to be ready at all times.”
     
    I fitted a second 1 mm diameter rod into the raised mounting on the side of the boiler, to carry the ‘intermediate gear’, which conveyed the drive from the primary gear to the gears on the faces of the driving wheels. After setting the model boiler onto its ‘boiler truck’, this part of the assembly appeared as shown below:
     

    My 3D-printed Boiler on its wheeled carriage
     
    I was pleased to find that the gears meshed together well, so the next step was to attach the boiler end plate, carrying the primary drive shaft: and its gear wheel.
     

    Assembly of the Main Gear-train
     
    These parts all fitted together well, so it was time to look at the thorny issue of the cross-head and its associated support structure.
     
    I decided to attach all the relevant parts to the end-plate of the boiler, before adding the completed assembly to the boiler itself and the main gear-train.
     
    I started by cleaning up the details on the end plate of the boiler since, in the small scale, some of the detailing had become a little obscured by stray filament, where the printer had attempted to negotiate some very convoluted paths.
     
    Once this was done, I used a reamer to open out the central hole in the end-plate to accept the 1 mm diameter brass piston-rod. I thought that the printed cross head might prove too frail but, in fact, the central hole opened out successfully, by careful use of a 1 mm drill in a pin-vice. I slid the end of the piston-rod into this hole, adding a drop of super glue to keep it firmly in place.
     
    For the two slide bars on either side of the piston-rod, I used 0.5 mm diameter brass rods. Again, I used a reamer to help insert the rods into the appropriate sockets on the boiler end-plate and in the cross head. I cut two slightly over-length rods and slid them into their places alongside the piston-rod.
     
    As the last part of this assembly, I added the rather fragile print of the triangular support structure. The two arms fitted into two notches on the sides of the end-plate. I put a small dot of gelled-superglue into each of these notches and then manoeuvred each of the arms into place, in turn, holding them until the glue ‘caught’. After re-checking the alignment of all these parts, I set the whole assembly on one side, to allow the glue to harden.
     

    My assembly of the Cross Head and its associated Rods.
     
    To call this a delicate operation would be something of an under-statement! The end bracket holding the outer ends of the slide bars is the smallest item I've ever printed and the main problem was keeping it from the clutches of the carpet monster😆 I show it being held on the shaft of a reamer, against my thumb for scale:
     

    End support held on a reamer
     
    Note the two small ‘ears’ above the bracket, which replicate those on the cross-head. These are supports for rods to operate the four-way cock by means of tappets, moved by the cross-head to change over the cock as the piston nears the ends of the cylinder. They were also used when starting, to ensure that this single-cylinder locomotive started to move in the desired direction. I’m afraid I shall omit these parts, as they are simply too fine (for me) to create at 4mm/ft scale.
     
    The next items to add to the end-plate were the chimney and its right-angle connecting pipe. A key part of the original design was that the exhaust steam from the four-way cock was directed up the chimney, so that the steam blast helped to ‘draw’ the fire and so improve the steaming of the engine. As I had anticipated, the tall slender chimney did not print very smoothly and, a length of metal tube would be a better solution. The printed one serves the purpose of showing the overall appearance of the engine.
     
    After gluing this assembly to the end of the boiler, the remaining task was to add the long connecting rods, between the cross-head and the drive-shaft at the opposite end of the boiler. I couldn’t manage to fix pins into the end of the cross head so the rods are glued together here. The other ends are pinned to the flywheel and primary gear crank. In practice, although the cross -head will slide, the movement is too tight for this to be considered as a working model … perhaps, next time, with a few improvements to those components that are really insufficiently robust at this scale 🙂.
     
    So, at last, the rather spidery contraption looks as shown below:
     

    My 4 mm/ft scale model of a Trevithick locomotive c.1803
     
    So, why did I do it? Partly of course because it was there but also, I wanted to place the earliest GWR engines within the context of what had gone before. Even the earliest GWR engines were rather late on the scene – 35 years later than this Trevithick engine, which is rather a long time in a period of rapid technological development.
     
    I can write about dimensions and show models against a ruler but a much more ‘real’ impression is formed when I place my models from different periods alongside one another.
     
    Below I show the Trevithick locomotive in context with some of my early GWR models placed on the same table. I believe this brings home much more vividly what progress was made during the first half of the 19th century!
     

     
    Mike
  22. MikeOxon

    Broad Gauge at Didcot

    By MikeOxon,


    General
    A visit to Didcot Railway Centre is always good, when in need of a little inspiration!
     
    In this case, I was invited along to help introduce my grandson to the delights of steam trains. At 3 months age, he seemed to enjoy a ride in the steam railmotor but was not too sure about the joggling over points.
     
    Meanwhile, I slipped away for a look around the Transfer Shed, where various Broad Gauge replicas are stored. Outside the shed, a length of broad-gauge track shows the details of the construction, with longitudinal baulks and packing under the rails themselves.
     

     
     
    With the sunlight slanting through the skylights, the shed had almost as much atmosphere as the goods shed at Farthing
     

     
     
    Near the front of the shed, the 'Firefly' replica showed how rapidly locomotive designs developed in the early years - the original of this locomotive dating from 1840. In the atmosphere of this shed, it's not difficult to feel like a time-traveller.
     

     
     
    Carriage designs took rather longer to develop, with the earliest type of 3rd-class carriage being an open wagon, while the open 2nd was not much better!
     

     
     
    Inside the shed, the Gooch single 'Iron Duke' was dozing peacefully, with the mahogany boiler-cladding glowing in the sunlight. The remarkable increase in dimensions from 'Firefly' is very obvious, when these engines are seen together. The driving wheels have increased from 7' diameter to 8' and, perhaps more remarkable, the boiler diameter was almost 4' 10". Notice, too, how that 'ship's funnel' towers over the diminutive carriage.
     

     
     
    I was intrigued to note that the curious inverted spring between the two leading axles of the Gooch design found an echo in the gas turbine locomotive no.18000, which was standing outside:
     

     
     
    Finally, what is this? sacrebleu...
     

     
     
    Only joking - the King actually looked quite splendid in this colour!
     
    Mike
  23. MikeOxon
    I have not forgotten about my plans to create a diorama, as described in my Broad Gauge blog. 
     
    While I was researching the early days of the GWR, however, I found myself thinking about what had gone before – back to the ultimate pre-grouping period!  This led me to Trevithick’s engines, of which I photographed a replica at Blists Hill Museum near Telford:
     

    Trevithick replica at Blists Hill Museum
     
    Trevithick was a remarkable inventor but, sadly, not a good businessman. He not only demonstrated, by 1802, that a compact high-pressure steam engine could be adapted to both road and rail uses but also that such a vehicle could be propelled by adhesion alone. In his Penydarren locomotive of 1804, possibly his most famous design, he turned the exhaust steam up the chimney, so creating the ‘blast pipe’ which was to prove an essential component of later locomotives. He sold all the rights to his designs and emigrated to South America to seek his fortune. He eventually failed there and died in poverty, back in England.
     
    His son, Francis, wrote a two-volume biography ‘Life of Richard Trevithick’, published 1872, which describes his father’s life and inventions. In Vol.1, page 181, there is an illustration of the Tramway engine that was built for South Wales in 1803:
     

     
    Next, as so often seems to happen when I start a new research project, an entire ‘can of worms’ began to open up!
     
    The book also notes, however, that “particulars are taken from Trevithick's letters where other evidences are conflicting . It is probable that more than one tramroad - engine was constructed in Wales at that time.” The dimensions listed above do not correspond with the associated drawings! For example by scaling from the drawing, if the wheelbase is 4’ 1” then the boiler is only about 5 feet long, while the flywheel is about 8’ 9” diameter, so there is no way it could have fitted through the Plymouth-works tunnel on the Penydarren tramway!
     
    Later in the book, there are references to three different engines, including the one that I saw (in replica) at Blists Hill museum, Coalbrookdale.
     
    “We have no account of the railway work done by the Coalbrookdale travelling engine of 1802. The Welsh tramroad - engine of 1803 took a gross load of 25 tons, at the rate of four miles an hour, over a bad road, with sharp curves and stiff inclines, and without load ran at a speed of sixteen miles an hour. The Newcastle locomotive of 1804 was, in general outline, similar to the Welsh locomotive, but in detail superior. The wheels were to run on rails instead of trám-plates, and were 9 inches farther apart than the Welsh locomotive, giving increased steadiness. The boiler and return tube were wholly of wrought iron; the fire -door and chimney were at one end of the boiler, and the cylinder and guide-rods at the other end, giving more room to the engineman than on the Welsh locomotive, which had all those things at one end of the boiler. The cylinder of the Newcastle locomotive was of the same size as the Coalbrookdale engine of 1802 , being 7 inches in diameter, with a 3-feet stroke, and therefore was probably made at Coalbrookdale, from Trevithick's drawings and patterns of 1802, with its regulating blastpipe and steam of from 60 to 145 lbs . on the square inch .”
     
    At this point, there is even a Swindon connection, as shown by correspondence between Joseph Armstrong and Francis Trevithick:
     
    “F. TREVITHICK , Esq . May 10th, 1870
    DEAR SIR,
    By this post I have forwarded a tracing of the old locomotive for Mr. Trevithick, and likewise some copies of an extract from the Gateshead Observer.' They would have been sent ere now, but I have had some difficulty in procuring an original from which to get a tracing, and have also spent time in hunting up this extract, and having it reprinted .
    Yours truly,
    JOSEPH ARMSTRONG Esq, Swindon.”
     

    In Plate V. , a is a steam-cylinder 7 inches diameter, 3 -feet stroke , fixed in the boiler ; b , piston-rod ; c, crosshead ; d, guides ; e , stay ; f, connecting rod ; g, crank ; h, driving axle ; i, fly-wheel ; j, gear-wheels ; k , four driving wheels, 3 feet 1 inch diameter, 4 feet 8 inches from centre to centre ; 1, four-way cock ; m, lever for working cock ; n, plug-rod ; o , cylindrical wrought- iron boiler, 4 feet diameter , 6 feet 6 inches long ; p, firegrate ; q, return fire - tube of wrought iron , 2 feet 3 inches diameter at the fire -door end, 1 foot diameter at the chimney end ; r, chimney ; s , fire-door ; t , railway of longitudinal timbers, 3 inches wide, 4 inches deep ; u, cross-sleepers, 4 inches wide , 3 inches deep ; 1 foot 1 inch apart ; gauge between wood rails , 4 feet 10 inches ; weight of engine in working order, 4 tons.
     
     
     
     
    Trevithick's 'Newcastle' engine
     
    After searching for more information, I found Anthony Dawson’s much more recent book ‘Before Rocket: The Steam Locomotive up to 1829’, published 2020, in which Chapter 1 reviews Trevithick’s work between 1802 and 1814.
     
    This text agrees that there were at least three similar locomotives. Dawson points out, however, that the Penydarren locomotive “was built to be convenient for the driver to work the engine and for the witnesses to see what was going on” He suggests that “this would probably rule out the cylinder being at the same end as the chimney. Thus, it is more likely that the Penydarren locomotive had the cylinder at the opposite end to the chimney and firebox, somewhat analogous with the Gateshead [Newcastle] Engine.”
     
    I do not know why he discards Francis Trevithick’s description and statements in reaching this conclusion, since the earlier work appears to be clear about the differences between the two engines.
     
    There is also the matter of a ‘replica’ built by The Museum of Wales (Waterfront Museum, Swansea), completed in 1981.  Their guidebook states “that the replica was built working from Trevithick’s original documents and plans (now in the National Museum of Science and Industry).” This leaves the question “which plans?”. Their ‘replica’ places the chimney at the opposite end of the boiler from the cylinder, unlike the illustration in Francis Trevithick’s book but similar to the later Newcastle engine
     
    Perhaps I am missing some recent piece of scholarship but it is hard to see why the layout of the later Newcastle engine was preferred for the Welsh replica over Francis Trevithick’s 1872 description of the Welsh engine. Francis T. did, however, note that there was conflicting evidence and that “It is probable that more than one tramroad-engine was constructed in Wales at that time”. As I noted above, the engine, as drawn in his book, could not have run through the tunnel on the Penydarren tramway, although reducing the size of the flywheel would be a relatively simple modification.
     
    It seems that, after a lot of reading and thinking, the can of worms remains open!
     
    Creating a Model
     
    Naturally, I felt the need to create my own model but then I found a 3D printable design, created for the Prusa printer on the ‘Printables’ website  This work is licensed under a Creative Commons (4.0 International License) Attribution—Noncommercial—Share Alike @ThorinOakenshield.
     
    This model, however, is a much larger and more sophisticated model than my own usual designs but I thought I might re-scale and simplify the design. Then, there is the question of ‘which engine does it represent?’
     
    I tried my method of overlaying the drawing on p.181 of Trevithick’s book over a still from the video of the ‘Printables’ model and … in all the major respects they fit well together! (note that the video image is not quite ‘side-on’)
     

    Overlay of Trevithick drawing (red) on ‘Printables’ model
     
    So, whether or not this is actually the Penydarren engine or another Trevithick prototype, I feel that I am close to the appearance of one of the very first locomotive engines ever to run on rails!  I decided to reduce the dimensions of my version, to fit a 4’ 4” gauge trackbed in 4 mm/foot scale, as the track gauge seems to be the only firm figure we have!
     
    To do this, I imported the drawing on p.181 of Trevithick’s book into ‘Fusion 360’ as a ‘canvas’ and then scaled it to the correct gauge at 4mm/foot scale. This confirmed the wheel diameter as 15 mm (prototype 3’ 9”).
     

    Drawing from Trevithick's book scaled in Fusion 360
     
    Next, I loaded the .stl file for the wheels, downloaded from the web, into ‘Fusion 360’ as a ‘mesh body’. I laid this body over the above drawing and adjusted the size until the wheel diameter matched the drawing. This needed a scale factor of 21.34%.
     
    I imported all the .stl files for the web model into the ‘Cura’ software and re-sized them all by the same scale factor.  Then I loaded all the re-scaled files into ‘Fusion 360’ as mesh bodies.
     
    I could then move each of the parts within ‘Fusion 360’ into its appropriate location around the boiler, as shown below against the ‘canvas’ backdrop:
     

    ‘Printables’ files, re-scaled and loaded into Fusion 360
     
    This confirmed that the re-scaled parts should all fit together as required. It also indicated, however, that some parts would be too thin to print successfully at the reduced scale. In particular, the boiler casing would be far too thin, so I decided it would probably be easier to design a new part for this component and, maybe, for some other parts as well.
     
    The next step will be to review all the parts for their suitability for printing at 4 mm scale and make modifications where necessary.  In the meantime, I show a couple of 3D views of the model, rendered in ‘Fusion 360’:
     

    Two rendered views of 3D-model assembled in Fusion 360 from ‘Printables’ files
     
    Mike
     
  24. MikeOxon

    Taking Stock

    By MikeOxon,


    General
    On one or two occasions, I have received comments along the lines of “we want a layout”. From the beginning of my exploration of the broad gauge, it has been my intention to produce some sort of layout or diorama to display the various models of rolling stock that I’ve constructed.
     
    Of course I already have a small layout carrying both narrow and standard gauge routes, based in Oxfordshire, towards the end of the 19th century. This layout continues to provide entertainment to my grand-children and I do not intend to replace it with a broad gauge version. Unfortunately, broad gauge railways in 4mm scale require considerably more space than a traditional 00 gauge layout, so I shall be restricted to something rather simple .
     
    At the beginning of this blog, I described how my exploration of family history led to my exploring the area around Bullo Pill and the Forest of Dean. I also found a very thorough Accident Report on a collision in November 1868, which provided detailed descriptions of the make-up of both the mail train and the cattle train that were involved in the accident. While I did not intend to model the accident itself, I did use these descriptions to recreate two trains of the mid 19th century period. My first thought was to lay out a simple section of track representing the cutting close to Cockshoot Bridge, where the accident occurred but soon began to realise that this would not make a very interesting scene.

    Simple diorama plan
     
    During the period when I was building the models for these two trains, I discovered the possibilities opened up by 3D printing . The restrictions imposed by Covid gave me plenty of time to practice my 3D modelling skills, using 'Fusion 360' software, and I was soon enjoying the excitement of creating models of prototypes that I had previously placed firmly in the ‘too difficult’ box.

    Mail train

    Cattle train
     
    Gradually, I began to realise that virtually any type of early 19th-century rolling stock was within my grasp, given the limited dimensions of the actual vehicle at that period. I got somewhat carried away and started churning out models of all sorts of prototype – whatever caught my fancy at the time!
     
    An advantage of creating small models by 3D printing is that once designed, they take very little time to print, such that I soon found myself with quite an extensive collection of models covering prototytpes that operated from the earliest days of the GWR.
     
    Although more of these prototypes than I initially expected did appear in the Bullo Pill and Forest of Dean areas, it was clear that I was also creating stock more appropriate for other areas, such as the South Devon railway and the original stretch of the GWR between Paddington and Maidenhead. This left me with much food for thought, when I came to think of how to create a scene that could be representative of all these areas.
     
    As a first step I assembled a few representative trains from the various models that I have made so far.
     
    My first model train shown below is based on contemporary illustrations by J.C. Bourne of Bath and Bristol Temple Meads stations. The very short wheelbase carriages (6 feet on 7’ gauge) did not survive very long and were ‘ordered off the line’ following a Board Meeting on 12th July 1838!

    ‘Argus’ (Firefly-class) with 1840s passenger train, comprising:
    luggage truck, closed 2nd, open 2nd, posting carriage, horse box, carriage truck
     
    When I first made a model of ‘Aurora’, I thought of these 4-4-0ST engines as primarily South Devon engines. Later, I discovered that several engines of this class were employed on trains working into the Forest of Dean from Bullo Pill, so they tied in with my earlier plans! To my surprise, no fewer than 11 of the ‘Bogie-class’ engines were deployed there between 1854 and 1861.
     
    My ‘removals’ train, shown below, was inspired by an article in the Broad Gauge Society journal ‘Broadsheet’ No.26, p10 , which featured the Bristol firm of Knee Brothers and their first recorded use of a Pantechnicon being transported by rail in 1847.

    ‘Aurora’ 4-4-0ST with Furniture removal train, comprising
    Henson patent Van, pantechnicon,brake van, horse box, luggage van
     
    I was very surprised to discover that engines of the ‘Sir Watkin’ class, original built as condensing engines for the Metropolitan Railway, served for a short time at Bullo Pill. I only know this because my wife’s great-grandfather was fined £1 on 26th April 1870 for “passing the danger signal running ‘Sir Watkin’ into collision with ‘Bulkeley”.
     
    I found that there had been another accident on the Forest of Dean line in 1863, when a train of 70 wagons broke free and led to a ‘pile up’, said to be 15 wagons high, which took 5 days to clear! After that, trains were limited to 45 trucks, although these were reported to be ‘12 tonners’. My collection of 12 ton wagon models was built when I was struggling with a problem of ‘stringing’ with my Prusa 3D printer, so they form a motley collection, including some poorly-printed models.

    ‘Sir Watkin’ with Bullo Pill coal train with seven 12 ton wagons
     
    My last group of models comprises three of the engines ordered to Brunel’s impossible specifications. 'Vulcan' was the first engine to be steamed on the GWR, having been delivered by barge to West Drayton in 1837. I confess that these are my favourite models and are currently displayed on a case on a shelf in the living room, where their gleaming brass-work always attracts attention. As Brunel once wrote “we have a splendid engine of Stephenson's, it would be a beautiful ornament in the most elegant drawing room.”
     

    Brunel’s engines: ‘Aeolus’ (rebuilt), ‘Vulcan’, and ‘Eagle’
     
    In addition to all these, I also have made a model of a piston carriage as used on the South Devon Railway:
     

    South Devon Atmospheric Railway piston carriage and train
     
    So, what to do with all these models?
     
    One common factor in the early operations of the GWR is their close association with canals and docks.
     
    At the London end, materials for construction of the new railway were brought by the Grand Union Canal to depot set up at West Drayton, the place where Daniel Gooch first started his work for the GWR.  Notably, the first engine ‘Vulcan’ was unloaded from a barge there through the use of lifting tackle and a convenient Elm Tree!  Later, coal was delivered by sea and canal from Newcastle to coke ovens established between the canal and railway at West Drayton. Similarly, the small dock at Bullo Pill was used for the export of coal brought down by railway from the Forest of Dean.
     
    The first major civil engineering work on the GWR was the viaduct at Hanwell, named after Lord Wharncliffe, who had chaired the committee leading the GWR Bills on their passage through Parliament.
     

    Wharncliffe Viaduct - by P.G.Champion 8th July 2007- Own work, CC BY 2.0 uk,
     
    Other characteristic features of the early railway were the Brunel-designed stations, the round-house engine shed at Paddington, and the prolific use of wagon turntables for the movement of rolling stock at stations by manual labour and horses.
     
    I have an idea that it might be possible to illustrate these various features in a ‘generic’ diorama designed to capture the ‘character’ of the broad gauge... not forgetting, of course, that Elm Tree 🙂
     
    The 1879 OS map of the area around Bullo Pill dock contains many of the features that I would like to represent. I could modify the ‘dock’ into a generic canal basin and rotate the main line running North-South over a viaduct on the left hand side of the map to run across the top as a backdrop to the scene.
     

    Extract from OS 25” maps surveyed 1879 CC-BY license as shown
     
    I’d be interested in any suggestions my readers might want to make about how this could become an interesting scene covering a wide range of potential presentations.
     
    Mike
     
     
  25. MikeOxon

    Six-wheel Luggage Van - 1861

    By MikeOxon,


    General
    One of the vehicles I need for my planned 1868 Mail Train is a Luggage Van, which was the last vehicle in the train that was involved in the Bullo Pill accident.
     
    When I noticed that the Broad Gauge Society (BGS) has launched a new series of laser-cut plastic kits, which included an early luggage van, I thought it would be interesting to try building one. As readers of my blog will know, I like to scratch-build as much as possible but there is always a lot to be learned from building kits and in seeing the various problems that their designers have overcome.
     
    The kit arrived, nicely packaged in a small cardboard box, with the various components collected together in self-sealing plastic bags. There was a coloured instruction sheet and a copy of the relevant sheet from the series of excellent data sheets, produced by the BGS. Six of these vans were built, with iron sides and wooden framing, in 1861.
     

     
     
    Another advantage of building kits is that someone else has had the task of getting together the small parts needed to apply the finishing touches. In this, case, however, it is a very basic kit and the only additional white-metal parts are springs and axleboxes (to the appropriate Normanville pattern), and buffers. Other parts, including roof, oil lamps, wheels, and details such as door handles, etc. still have to be provided by the builder.
     
    According to the instructions, the first step is to remove a few small plastic parts from the floor piece. When separated, these are very small and light components, so I immediately put them into one of the self-seal plastic bags, to try and minimise the chance of their getting lost! Once separated, I cleaned the burrs left behind, using emery boards intended for smoothing finger nails.
     
    Most of the plastic parts are described as ‘Rowmark’ material, which is a laser-etchable plastic that can be solvent welded. Most are cut from 30 thou (0.8 mm) thickness plastic sheet, with some of the larger parts and overlays of 35 thou (0.9 mm) sheet. While it would be fairly easy to cut out similar parts with my Silhouette cutter, that machine is limited to cutting 10thou (0.25 mm) styrene, so several layers would have to be laminated to make a strong structure.
     
    Of course, if cutting out your own parts, the major tasks lie in designing the various components and then preparing the drawings, to produce an accurate and robust model – something that is completely avoided by buying a kit! The components in the kit are well-designed and include various tabs and slots to assist assembling them in accurate alignment. The slots in the sides are cleverly placed, so that they are subsequently hidden, when the outside framing is added.
     
    The first part of the assembly is to locate the various internal partitions into the slots in the floor piece. I used Slaters Mek-Pak as the solvent and noticed that it seemed to need more time to ‘take’ than when used on polystyrene card. On the other hand, as I discovered when some solvent leaked under my fingers that were holding the parts, the solvent does not damage the surface as much as can be the case with ordinary plastic card.
     
    The sides are fitted next, ensuring that the tabs on the sides of the partitions locate into the slots in the body sides. Once the joints have hardened, the end pieces are then added. It’s important to hold the sides in the correct positions, relative to the ends, since the are no tabs to assist with correct alignment at these junctions. The outside edges did not all align perfectly but it is not worth trimming them at this point, since the overlays to represent the outside wooden frames have to be added next.
     

     
     
    It’s now time to add the outside frames and, here, I encountered the first problem. The instructions state to stick the detailed ends onto the inner box and to sand the edges flush with the sides. When I carefully aligned the small holes for the buffer shanks in both the main body and the overlay, I found that the framing was quite a lot wider than the end of the body, so that sanding down the edges removed almost all the vertical part of the framing at one side.
     

     
     
    I’m not sure whether there has been ‘double accounting’ in the kit and that the ends of the side overlays are meant to replace these parts of the end framing. The prototype vehicles were constructed from iron sheet, which was presumably much thinner than is represented by the plastic of this kit. Only the outside frames were of wood.
     
    The next step is to add the side frames. These are both labelled ‘J’ in the instructions but the two sides are, in fact, mirror images of one another, so not identical. The important things are to make sure that the window openings, at one end, are aligned correctly with the openings in the inner sides, and that the laser-engraved detail is on the outside. A little more sanding is needed to remove any slight overlaps at the ends. Once this is done, the main body is complete and the etched engraving on the side frames looks very nice.
     

     
     
    Once the body is complete, the next task is to add the underframe sides. These are in a transparent material and there is a warning, at the top of the instructions, that “the Perspex is delicate until laminated together”. Elsewhere, it is stated that the ‘mylar’ needs to be stuck with small amounts of superglue.
     
    There are lots of small holes in the side frames, which have to be lined up with one another. I ran in a small drop of superglue, starting at one end, while squeezing the parts together. Inevitably, the superglue oozes out through the many small holes (and fills them) and goes all over your fingers! It also marks the hitherto smooth sides of the frames. When laminated, it is difficult to avoid warping of the frames, since there are only two layers. The Perspex/mylar continues to be delicate after laminating, as I discovered when I tried to straighten the warping and the material promptly snapped. I’m not sure why the designers chose this material and method of construction but I may make some frames of my own out of either polystyrene or brass strip.
     

     
     
    The remaining parts included in the kit comprise windows, with separate frames, some corner brackets, on a small flexible 'fret', for the outside frames, and white-metal springs/axleboxes and buffers. There are also some small parts that were cut off from the floor plate. Despite my precautions, one of the tiny tie-bars went AWOL for the photograph but turned up later, from where it had ‘skipped’ to the side of my worktop! There’s a thread in the Forums about ‘Why are modellers so clumsy?’
     

     
     
    I shall delay fitting these parts until after making final decisions about solebars and axle guards.
     
    As I mentioned at the outset, this is not a ‘complete’ kit and I still have to construct my own roof and think about what additional fittings I shall add, including oil lamps, hinges, grab handles, door handles, etc. The modeller still has quite a few decisions to take after building this van body.
     
    On the subject of other Forum threads, there has been some discussion about Broad Gauge horseboxes, with a wheelbase of only 6 feet (1.83 m), in Mikkel’s Workshop Thread.
     
    Well, it wasn’t only horses that had to suffer in such vehicles, as some very early passenger carriages had this same wheelbase!
     

     
     
    Having seen this drawing, I find it hardly surprising that, according to the diary of George Gibbs (an early GWR Director), these 4-wheel carriages were ordered off the line at a Board Meeting on 12th July 1838! George Gibbs’ diary contains many interesting descriptions of the tribulations which the GWR suffered in those very early days.
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