MikeOxon

I like to try and correct 'fake news' 😄 I agrrr that it must have been an exciting day for the BGS. I suspect there are quite a few followers of the 19th century GWR who hope that some drawings of the semi-mythical 4-2-4T No.9 will eventually turn up somewhere. Mike

I've been on a steep learning curve and intend to write about it in Part 2. The truth is that it didn't work well in practice and not just because the appropriate materials weren't available. There were just so many shortcomings, when it came to adapting the idea to railway operations. No points, no cross-overs, and very little control for the 'driver' of the train.

Introduction Having worked my way back to the very beginnings of the GWR, it’s been hard to think of where to go next. I’ve enjoyed exploring those odd-ball engines that Brunel ordered for his new concept of a railway, even though they proved to be disastrously undersized. Nevertheless, several of them had quite long lives as branch-line engines. I do enjoy ‘bringing to life’ forgotten areas of railway history and, for the broad gauge, the ultimate in odd-ball ideas was, perhaps, the atmospheric railway that Brunel decided to recommend for the South Devon Railway. Atmospheric Railway showing Pipe and Pumping Station at Dawlish by Nicholas Condy (1793-1857) The basic idea was to move things along a pipe by evacuating air from the pipe ahead of the vehicle, so that atmospheric pressure would push from behind. This concept found some long-lived applications in shops and other businesses, where it was used to carry paperwork and cash in small canisters around a building. In 1840, two engineers, Clegg and Samuda, laid out a half-mile long track at Wormwood Scrubs, where railway carriages were drawn along by a piston, placed within an evacuated iron pipe set between the running rails. Several engineers were invited to view the demonstration and, whereas Stephenson dismissed it as a ‘great humbug’, Brunel was captivated and went on to propose it for use on the South Devon Railway. He wasn’t alone and the idea was adopted by a few other railways, including the Nanterre to St Germain railway in France. The first to be built, in 1843, was the Kingstown & Dalkey Railway, on the outskirts of Dublin. It was only one and three-quarter miles long and the atmospheric system was used to take trains up an incline, from which they returned by gravity. A trial was also made on a 5-mile stretch of the London, Croydon & Epsom Railway, authorized in 1844 and opened in January 1846. Many problems were encountered and in May 1847 the whole line was converted to locomotive operation. Typically, Brunel’s plans were more grandiose. On Brunel’s recommendation, the South Devon Railway laid fifteen miles of single track from Exeter St David’s to Teignmouth, later extended by a further five miles to Newton Abbot. The intention was to apply the atmospheric system all the way to Plymouth, so Brunel allowed some unusually steep gradients along his surveyed route, on the assumption that they would be operated by atmospheric traction ... but matters never got that far! Atmospheric operation of the line was very short-lived: public operation began on 13th September 1847 and within the year it was all over!. The last atmospheric train arrived at Exeter during the night of 9/10 September 1848. This isn’t the place to go into all the reasons for such a catastrophic failure – suffice to say that the multiple reasons were both technical and economic in nature. Misconceptions So why do I want to make a model? My main reason is that there are serious misconceptions about what the railway actually looked like. A lot of credence was given to images based on Clegg and Samuda’s Patent Application, which actually bear very little resemblance to what was actually built. The illustrations were only intended to indicate the principles of operation, as shown below. Schematic diagram from Samuda and Clegg’s Patent on atmospheric railway. Unfortunately, a commercial artist and writer, Robert Barnard Way, active from 1930 to 1958 created an atmospheric railway scene based on Nicholas Condy's painting of Dawlish (above), with the addition of a train headed by a simple flat car, as shown in the Patent diagram. There are now a great many copies of this image in circulation, so I shall avoid perpetrating this error. A true description of the piston carriage used on the SDR came to light during a meeting of the Broad Gauge Society (BGS), held at Bristol Museum in 1993. There was an opportunity while they were there to browse through the Woodfin Collection, where some BGS members were astonished to discover a real bombshell. Negatives 14471, 14894-14896 and 16141-16150 actually recorded drawings of one of the elusive South Devon Railway piston carriages. Paul Garnsworthy of the BGS created new drawings from the rather faded images and published a pair of articles, including his drawings, in the BGS Journal ‘Broadsheet’ issues 44 and 46. (available to BGS members in digital format) In order to set the record straight, I decided to create a model based on these drawings, using my usual methods of extruding from drawings by means of ‘Fusion 360’ software. Creating my Model The first step was to import the drawings from ‘Broadsheet’ as a ‘canvas’ in ‘Fusion 360’. After scaling to 4mm/foot, I copied the main outlines of the sides and ends, before adding details of doors, windows, and panelling. All these were created by means of the ‘rectangle’ and ‘3-point arc’ drawing tools My sketches of the carriage side overlaid on the ‘canvas’ I then used the ‘push-pull’ tool to raise the mouldings above the main extrusion of the side, to create a solid model. The ends of the carriage were created in exactly the same way from the appropriate drawings. The sides and ends were all created as separate ‘bodies’ within ‘Fusion 360’. The floor was created as a simple rectangle and the roof was similar except for an arc profile. I added two oil lamp housings to the roof, placed to be shared between the 2nd and 3rd class compartments, This was a common practice in the early days, when any sort of lighting was considered a ‘luxury’! Once all the parts were extruded, I created a rendered image of the complete assembly in ‘Fusion 360’. The colour of these carriages is unknown. Brown was the standard colour used on both the GWR and the SDR but there is evidence that at least some 2nd class SDR carriages were painted green. I decided to use green, simply to provide a contrast to my usual stock. Accommodation in the prototype comprised two 2nd class compartments towards each end and a central area for 3rd class passengers. The piston carriage was designed to be bi-directional and was not turned at the end of a journey. Because much of the SDR line ran along the coast, the two sides can be referred to as the ‘seaward’ and ‘landward’ sides. Brakes were only fitted on the landward side so the driving position was offset to this side at both ends of the carriage. my rendered piston-carriage body created in Fusion 360 For printing, I divided the components into just four parts – 2 sides, roof, and a floor combined with ends and partitions. The four components ready for ‘slicing’ and printing. This division into components allowed me to lay the sides flat on the printer bad, so that there was no need to provide additional support to the window openings. The roof is flat on the underside and the other parts are printed from the floor upwards. I could separate the ends, if this proved necessary to achieve clear window openings but, in practice, I have found that my printer copes well with small simple rectangular openings like these. Printing my Model The printing all went smoothly, including the floor and partitions, where I had hoped that the window openings would print reasonably cleanly without additional supports. There is a little stringing visible (I used the Geeetech printer) but nothing to cause any difficulty. Floor and Partitions on Geeetech E-180 printer bed I then printed the two sides and the roof, which included two oil-lamp housings, shared between adjacent compartments. I continue to be amazed by what my printer can achieve. In this case, I could see light through the small holes in the lamp covers that I had included in the 3D model,. My 3D-printed Piston Carriage Body with oil-lamp housings Of course, this was just a straight-forward carriage design. I now have to tackle the underframe, with its attachments to the atmospheric pistons. On the prototype, these were pivoted such that they could be raised if the carriage had to pass over crossings in ‘ordinary’ track. I intend to represent them in the raised position or, if I can manage to do so, I may even make them hinged! I anticipate that creating them, such that they can be 3D-printed, will be a challenge and I suspect that some ‘hybrid’ construction methods will be necessary. Mike Feature Photo: watercolour by William Dawson (1790-1877) - "view of Newton station, via Brunel's Atmospheric Railway"

as Beerbohm put it - " that antique station, which, familiar to them and insignificant, does yet whisper to the tourist the last enchantments of the Middle Age."

I agree entirely and usually follow the same plan. My concern was that the Geetech printer dealt with the small features far more successfully than the Prusa although th Prusa has fewer artefacts in the flat areas of the planking. I have accumulated quite a collection of BG 12 ton coal wagons in attempting to resolve the problem with various changes to the Prusa slicer settings. Now, I shall try using Cura and see how it goes - more wagons to come!!!

Thank you very much for that, Mike, I'll give it a try. I have been continuing to use the Geeetech while my last print head keeps going but replacements are no longer available.

Thanks njee20 but it was just an 'interesting' design to tackle, while I think about where I want to go next.

It' just that I like to try the quirky and unusual and see what challenges they throw up, when it comes to modelling them. As this was just an experiment, I have printed at only 0.15 mm resolution, hence the banding but, as you say, the printed vinyl will cover most of that, although in reality it's not at all obvious.

Perhaps it's related to the quotation on you 'signature' panel, Edwardian "Norfolk is cut off on three sides by the sea and on the fourth by the West Norfolk Railway" - E L Ahrons I think it was perhaps the colouring that give it the Transatlantic look

There's something about the buildings that gives Mumbling on the Hill an American or Canadian look.

Thank you, Mike. I often just use a 200°C soldering iron to 'weld' parts together but this was too delicate for that method.

Thank you Jason. this has been suggested by Prusa as a possibility. The trouble is that the same reel of filament prints well on my Geetech E180. It's a bit disappointing that the Prusa is causing me problems but I am forced to change because new print-heads are no longer available for the E180.

Background Several years ago – 2006 in fact – I was driving away from a visit to Blaenau Ffestiniog slate quarries and noticed that the last train of the day was due to arrive at the railway station. It turned out to be quite a long wait, as the train on the Festiniog Railway was in trouble and eventually arrived with a broken flexible steam pipe to one of the power bogies. With a sense of ‘make do and mend’, the trailing end of the pipe was lashed up and the train then made a very late start for Porthmadog, relying on just one power bogie for the downhill trip Broken Steam Pipe of ‘David Lloyd George’ At that time, my small model railway was in abeyance, although I did think briefly about the Langley Models kit, which seemed rather basic and also required the purchase of an American diesel to provide the chassis. Now, there is the Bachmann model, which looks very nice but, at £200, this is too expensive just to satisfy a vague whim. It’s too long anyway for my rather tortuous narrow gauge track around the North Leigh quarries. I did feel an ‘itch’, however, to try one as a 3D modelling task. I felt it provided an interesting challenge to lay out the components in such a way that they could be printed on my basic FDP printer. Steps to Creating My Model I found a drawing by Ian Beattie of a ‘typical’ Festiniog Double Fairlie in ‘Railway Modeller‘ November 1992, which I have used as a basis for my model. I also found a very helpful photo of an unclad ‘Merddin Emrys’ at Boston Lodge on the Festiniog ‘Facebook’ pages. This showed me several normally hidden details of the boiler and its supporting structures. The Footplate Following my usual method, I imported the Ian Beattie drawing, as a ‘canvas’, into Fusion 360. I started by extruding the footplate from the plan view in this drawing collection, as shown below. I designed this so that the top surface was completely flat and could be laid on the bed of my FDP printer Extruding the Footplate in Fusion 360 Since I do not have a practical application for this type of engine, I am treating it simply as a design exercise. The Cab and Firebox The next challenge was the central cab. Since I had included the parts of the sides below the footplate and the firebox plinth in my initial footplate component, I had to create a part that would sit flat on the firebox plinth. I first drew the front and back ends of the cab by tracing over the drawing. The sides were a little more complex, because of the ‘joggle’ in the width, at mid-height. I created a 1mm ‘offset’ drawing inside the edges of one of the end walls of the cab and then extruded this profile along the length of the cab to create both sides and the roof. I then drew the outline of the side opening on one side of the cab and used the ‘push-pull commend to cut out these openings through the entre width of the cab. These stages of my construction are illustrated in the following drawing: Steps in designing the Cab for my Model After the extrusion described in Step 1, my next Step 2 was to add the other end wall to the cab and then complete the assembly by adding a floor, which would sit on the firebox plinth, when printed. Step 3 shows the twin firebox, which was a separate extrusion and, as in the case of the cab, I drew the detail of the fire doors on one side of the box before using the push-pull tool to emboss the details of the two doors. I also added the shaft for the handbrake. Similarly, I added some details of the reversing lever on the opposite (Driver’s) side of the firebox. Step 4 shows the complete cab with the firebox inside, aligned over the footplate, which I had extruded first. Note that the large holes through the length of the firebox and cab ends are to allow a brass tube to be passed along the whole length of the printed model, to act as a ‘spine’, both to align the two boilers and to hold everything together. The Side Tanks The next challenge was presented by the four side tanks. Those on the Fireman’s side contain coal bunkers while, on the Driver’s side, there are tool boxes on top. These tanks form mirror-image pairs at each end of the engine. To create the tanks, I started by extruding from a rectangular base to the height shown on the drawing,. On the prototype, the tanks have extensions on their inner sides to fit around the boiler. I created these by drawing the end profile and extruding this along the length of the tank. I added the tank fillers by extruding upwards from the top surfaces of the tanks, after drawing their profiles. The coal bunkers were extruded in two parts: a rectangular base and the (initially) vertical plate behind the bunker. I then used the move tool to tilt the plate to the angle shown on the prototype drawing. After joining the two parts together I moved them into position on top of the relevant tanks (on the Fireman’s side) as shown below: Coal Bunker on Fireman’s Side Adding some Coal As an interesting exercise, I thought that I would try adding a simulated coal load by means of 3D printing. In a previous post I described how I used an extension to Fusion 360 to create a surface texture. This comprised a ‘plug-in’ for 'Fusion 360' called ‘Image2Surface’, which adds the capability for 'Fusion 360' to create a textured surface from a 2D image. Downloading the appropriate software and then getting it to work was not straightforward but, fortunately, I found a 'YouTube' video, which explains the procedures very well. In my previous post, I created a textured surface based on a photograph of gravel ballast. It occurred to me that the appearance was quite similar to that of small coals in a bunker, so I made a copy of my previously created texture and used the cutting tools in ‘Fusion 360’ to make a rectangular section to fit in the top of my coal bunker. The result is shown below: ‘Coal’ texture panel above my rectangular Coal Bunker. With appropriate colouring, I feel that the gravel texture provides a reasonable representation of the top of a filled bunker! There is an important caveat when creating surfaces by this method – they can involve a very large number of facets and vertices, which results in very large file sizes. Even though my model bunker top only measures 4 mm X 17 mm, the .STL file that describes it occupies a staggering 258 MB. Of course, I could easily reduce that size by reducing the level of detail but the act of ‘slicing’ the model for printing reduced the size anyway, to a manageable level. This is a technique to bear in mind for small applications but not really suitable for creating large areas of ‘facings’ on buildings and other scenery. The Boilers and Smokeboxes The two boilers are identical and are simple cylinders, formed in exactly the same way as I have described for many earlier engine models. Similarly, the boiler fittings and smokebox all followed my usual methods. Once I had brought all these parts together within the ‘Fusion 360’ software, my 3D model looked like this: My 3D Model of a ‘typical’ Double Fairlie Printing my Model As usual, I printed my model as a set of components, arranged so that each could be built up from a flat surface. With experience I have found that my FDP printer is far more tolerant of overhangs than I had initially thought. I now take more ‘liberties’ in the design and find that quite large openings, such as where the boilers fit into the cab ends, can be printed without any additional supports or ‘helpers’ I have previously printed smokeboxes as open tubes and added the curved front door separately. This time, I tried printing the smokebox as a single item and was surprised to find that my printer bridged the hollow centre behind the curved front without difficulty. I suspect that the ability to bridge gaps during printing depends strongly on the temperature of the filament when it is extruded. The largest single part was the footplate and I printed this ‘upside down’ on the printer bed, taking advantage of the extensive flat surfaces. Note the opening in the cab side, which is ‘bridged’ without any additional support. Footplate Model on the Printer bed Next, I printed the cab, which comprises the end and upper side walls, up to the level of the roof. Note that the lower side walls and a plinth for the firebox were included as parts of the footplate component. 3D-printed Cab, mounted on Footplate The holes in the cab end walls are to accept a brass tube which runs the length of the model and holds the boilers and smokeboxes in alignment. This tube also adds weight to the structure. I printed several of the smaller parts – sandboxes, domes, and chimneys – together as a group. They all printed surprisingly cleanly and despite the small contact areas remained firmly attached to the printer bed. This set of parts took just 12 minutes to print! 3D-printed Small Components For this model, I set the layer height when printing at the ‘normal’ setting (0.15 mm) rather than the ‘fine’ setting (0.10 mm) , which I use when there are rows of rivet detail or other detailed structures. This does mean that some ‘banding’ is visible in the photographs but is not noticeable at normal viewing distance on a 4 mm scale model. My complete set of parts after printing is shown below: 3D-printed Components of my Fairlie model The first step in assembling the parts was to place the twin-firebox unit within the cab. I then inserted the central rod and slid the two boilers and smokeboxes over this, to check the overall alignment – which was good. I used superglue to hold this partial assembly together. I have read in some places that superglue does not work well on PLA plastic but that is not my experience, provided it is given time to polymerise. In fact, I have sometimes found it difficult to separate parts that I have inadvertently not aligned properly! Adding the tanks came next. It’s important to get each tank in its correct position since they are all different! After a little trial and error, I found that the best method was to glue each tank to the appropriate end of the cab, ensuring that they were aligned correctly with the two boilers and that the tanks and cab all sat flat on a plane surface. 3D-printed Model with tanks glued to cab Once the bonds had hardened, I added the various small details – sandboxes, domes, and chimneys - by means of tiny drops of glue under each, then holding them in position for a few moments until the joint was firm. Finally, I could glue all this ‘upper’ structure to the footplate, which was rather flexible on its own but gained rigidity once glued to the lower surfaces of the tanks. The complete assembly then looked as below: My 3D-printed double-Fairlie model I have thoroughly enjoyed designing and constructing this model. Of course, the issue of the two power bogies remains! I intend to apply lining and lettering by means of printed vinyl overlays as described in my earlier series of posts about ‘lining and lettering’. Mike

I'm sure your workroom would have looked very nice in overall red oxide colour 😀

You've ended up with something reminiscent of 'Galloping Gertie', absorbed into the GWR from the MSWJR and numbered '24'. She is reputed to have taken an express from Bristol to Swindon, following the failure of 'King George IV'.

What time period are we supposed to be? Flashing indicators did not appear in Britain until mid to late 50s.

Perhaps Mr Price knows Mr M G Williams and could find out more?

This advert from 1899 may be of interest Mike

In the days before railways, cows for milk were often kept in quite small yards amongst the houses in towns - as were hens for eggs and a pig being fattened! Visitors to the SS Great Britain in Bristol can see the cowshed on the open weather deck, to provide milk during a voyage: Mike

I can remember, on a campsite in rural France in the 1960s, collecting milk in a jug from a cart rather like that one.

Don't forget the bicycling craze of the 1890s, when it briefly became fashionable for ladies to be seen cycling in Hyde Park and a whole new style of 'Rational Dress' appeared. There were also fulminations from some pulpits about the moral evils of ladies wearing bloomers 🤯

I tried enhancing the photo as well as I could and feel that the name on the splasher of the leading engine is more like to be Princess Beatrice than the other suggestions. I have seen several similar views taken near Hayes. See for example the collection at https://railway-photography.smugmug.com/GWRSteam-1/Dean-Locomotives/Dean-assorted-designs/Dean-Single-3031-class/i-v3DTVQH/A

My main reason for model-building is to be able to visualise some of these early engines 'in the round' 3-view drawings and posed photos can only tell us so much but the real 'character' of an engine often only becomes apparent when you can look at it from different angles. It's great to see No.34 coming through like this 😀

Your problem rang a faint bell with me. It may be something completely different but I recall that back in 2014 I had a problem with rounded corners when using Silhouette Studio v.3. When I reverted to Studio v.2, the problem disappeared. If you still have a copy of the older version, you might like to try it.

Thank you. I sometimes feel that my modelling interests have gone rather 'out on a limb', so it's good to know that that are still of interest to some people. Some of my subjects, especially the early engines were themselves rather 'fantastic'!