RosiesBoss Posted September 13, 2017 Share Posted September 13, 2017 Introduction The GWR developed a family of designs of 4-4-0 which, in their general appearance, were unique to that railway. Most were double framed, as described in Ref.1. The exception was the Churchward County class 4-4-0. After the grouping of 1922-23, several other inside-framed 4-4-0s were added to the fleet, including three classes from the Cambrian Railways. Most non-standard 4-4-0s were soon scrapped, but the prototype for this project lasted in service until 1933. My eclectic collection of GWR locos includes representatives of several standard 4-4-0s: 3283 Comet (Keyser) 3440 City of Truro (Motorised Airfix) 3713 City of Chester (Motorised GBL) 3814 County of Chester (Kitbashed Airfix) 3293 Earl Cawdor (Scratchbuilt) 3265 Tre Pol and Pen (Kitbashed Airfix) The collection also includes models of quite a few classes that ran on the more lightly-laid lines taken over from the Cambrian Railways: 848 (517 class, rebuilt Airfix) 1196 (rebuilt CR Seaham class – scratchbuilt) 1331 (ex- W & C – kitbashed Hornby) 1376 (ex-B & E – scratchbuilt body, Hornby chassis) 908 (CR small goods – kitbashed Lima/Hornby/Dapol) 885 (CR 73-class – kitbashed Mainline/Bachmann/Tri-ang) 2322 (2301 class – Hornby) 2517 (2301 class – Mainline/K’s/Airfix) 3283 Comet (Duke class – K’s) 3262 Tre Pol & Pen (Kitbashed Airfix) One of the gaps is clear, isn’t it? Yes, obviously – an absorbed CR 4-4-0 94 class! Just like my latest completed project (ex-RR 83), I could find very few photos of the class in service and the drawings in Ref. 13 were basic, to say the least. Nevertheless, I pushed on. Where possible, I like to adapt working chassis from models of generally similar prototypes, provided that the wheelbases are reasonably close. Here is a comparison of the 94 class with other 4-4-0s for which working chassis are or have been made: Front bogie Bogie to 1st driver Driver spacing CR 94-class 5’6” 7’3” 9’3” GWR County 7’0” 8’6” 8’6” GWR Dukedog 6’6” 7’3” 8’6” GWR Bulldog 6’6” 7’3” 8’6” GWR City 6’6” 7’6” 8’6” GCR Director (GBL) 6’9” 8’9” 10’0” NBR Scott 6’6” 7’7” 9’6” LMS 2P 6’0” 7’2.5” 9’6” LMS Compound 6’6” ? 9’6” LNER D49 6’6” 8’5” 10’0” Tri-ang or GEM L1 - - 10’0” SR T9 6’6” 6’9” 10’0” Tri-ang Polly/Nelly - - 8’3” Hornby Smoky Joe - - 8’3” All of the commercial chassis required some compromises. I did bid on a few chassis on eBay, but in light of the compromises to be made, their prices went too high. I also considered chassis kits from the likes of Comet, but none of these were close enough, given their prices. I decided to scratchbuild the chassis from some square-section stainless steel that found its way into my scrapbox. I thought about using loco body parts from a GBL Director model that I bought for its tender, but the boiler was just too big. On the other hand, the upper tender moulding could be butchered into a CR one, to be mated with a modified frame from a Tri-ang B12 tender, in the same way as I did for my model of 885. Therefore, most of the loco was to be scratchbuilt, with the tender a kind of kitbash. Techniques used were those inspired in Refs. 15 and 16. The only drawing of the loco I could find was that published in Ref.13 – a simple side elevation, which provided most of the main dimensions. Much use was therefore made of photos published in Refs. 9 to 14 and 18, together with the occasional image advertised on eBay. The final result may not be of museum quality, but the project has been an interesting challenge to undertake. Parts List 0.5” square-section stainless steel tube 24mm dia Romford driving wheels Romford axles, bearings & driving wheel cranks Rear bogie frame from Dublo 2-6-4T 13mm dia bogie wheels 14mm dia tender wheels Misc. sheet brass and copper Misc. polystyrene sheet Brass handrail knobs 0.4mm dia. phosphor bronze wire for pickups and handrails Stainless steel reinforcing strips from discarded car windscreen wiper blades – for coupling rods GBL Director model Tri-ang B12 tender frame Mashima 1420 motor 2nd-hand gearbox (brand unknown) Brass dome (turned up on lathe) Brass safety valve & base (turned up on lathe) Brass chimney (turned up on lathe) Brass whistles (Peter’s spares) Dean-Churchward buffers (Alan Gibson) Hornby spare smokebox door (Part L6996) Backhead from spare Airfix City of Truro kit Brass rod for feedwater and vacuum ejector pipes Printed circuit board material for pickups Hornby tension-lock couplings Misc. brass BA screws, washers and nuts 6BA nylon screw/nut/washers Humbrol enamels HMRS Pressfix transfers Wire-wound guitar E string Spent 0.22” calibre shell casing Construction Chassis An old Dublo 4MT rear bogie was taken and its wheels replaced with new insulated 13mm dia ones. A new swing-link was fabricated to attach it to the main frames. A piece of SS square-section tube was cut just over-length and holes drilled for the axles. These were undersized, to allow for a little adjustment if any were slightly off the mark. They were reamed out to accept the Romford axle bearings. The front of the frame was sculpted to accept the front bogie and wheels. The bogie was temporarily attached to the frame with an 8BA screw fitted to a tapped hole. The driving wheels and axles were fitted and the assembly tested to see if it would roll easily and negotiate the curves and points on my layout. Any tightness or pieces of frame fouling the bogie wheels were sorted out until all worked well. A second-hand idler gearbox was fitted with a Mashima MH1420 can motor and test fitted to the chassis after cutting a suitable hole in the top of the (box-section) frame. Any tightness in the assembly was eased until it ran sweetly. Coupling rods were then made from SS strips recovered from windscreen wipers. These were fettled until there was no binding in the assembly. A pickup assembly, including a greencap capacitor, was fabricated and installed on top of the chassis, under the motor. After testing to confirm the directions of travel, the pickups were connected to the motor. Test running of the completed chassis revealed that the Hornby bogie wheels first selected had oversized flanges which caused short circuits against the main frame, so these were replaced by finer ones (probably Alan Gibson). Testing with the body attached showed the model to be slightly nose-heavy, so around 10g of sheet lead was bent to shape and inserted into the chassis, below the cab. This cured the problem. The tender coupling was fabricated from scrap brass and a small length of 1/8”W threaded brass. Body Most of the body was built up from copper/brass bought cheaply from my local scrap metal merchant, who has a policy of allowing customers to browse around his warehouse to pick and choose whatever they need. He charges around $1.00 per kg for copper & brass. One can make a lot of models with 1kg of thin sheet copper or brass. (The SS for the chassis came from him also.) A basic footplate was first cut out from thicker copper sheet. This was to provide the foundation of the body. The openings for motor, gearbox, wheels and coupling rod splashers were marked out. These openings were then cut out on my scroll saw (running slowly with a fine blade) – undersized – then the footplate was test fitted to the chassis and openings adjusted until there was a good fit with no binding or fouling. Splashers for the wheels and coupling rods were soldered up from 0.005” brass sheet. A paper pattern for the cab sides was cut from a spare 4mm scale drawing of the loco and used to mark out two sides in 0.010” modellers’ sheet brass. These were cut out and adjusted until they were a perfect fit against the reference drawing. The cab sides were soldered into position on the footplate and the coupling rod splashers were soldered into place behind them. The wheel splashers were then soldered into their positions. The resulting assembly was test fitted to the chassis and carefully trimmed until there was no binding of the driving wheels. Front buffer beam, drag box beam and footplate valences were added. In the same way as the cabsides, a paper pattern for the dummy frames showing above the footplate was prepared and then used to mark out some 0.005” brass sheet. The frames were then cut out and soldered to the footplate. Two lengths of 1/8”W threaded brass were soldered to the footplate. The front one (replacing the temporary 8BA screw) to both secure it to the frames and provide a mounting point for the bogie swing-link and the rear one to both secure it to the frames and provide a location for the loco-tender coupling. Assembled to the chassis, the body now looked like this: A length of ¾” dia plumber’s copper pipe was used to make the boiler, opened up around the motor/gearbox assembly and formed into the bottom of the firebox. Small sections were also cut away to clear the driving wheels. Another short piece was cut, slit lengthwise, opened slightly and slid over the front of the pipe to represent the smokebox. A simple saddle to support the rear of the smokebox was cut from 0.010” brass and soldered into place on the footplate. A wrapper with full rivet detail (impressed from inside) was cut from brass shim to be soldered around the smokebox and to locate outside the tops of the front dummy frames, as seen in photos of 1043 taken in the early 1930s (eg in Refs. 11 & 18). The Belpaire firebox was built up from 0.010” brass sheet soldered to the copper pipe, then trimmed to shape. Branding stamped into the plumber’s pipe was filled with solder, then smoothed back. A piece of 0.010” brass sheet was cut to the shape of the front of the smokebox, including the “piano” valve cover. The remainder of the boiler/firebox/smokebox unit was then soldered together. A piece of copper sheet was cut to shape for the front of the cab and undersized openings made for windows and to clear the rear of the motor. The cab front was soldered to the cab sides and then the boiler unit was test fitted to the frames. After correcting the shape of the firebox, the cab front was marked with that shape and the windows opened up to suit. Cabside beading was made from modellers’ L-section brass and soldered into position. Cabside handrails were cut from 0.3mm dia phosphor bronze wire and soldered into position. The boiler unit was affixed to the footplate and cab with 5-minute epoxy, which had the additional role of filling any imperfections in the fit. After cleaning off any excess epoxy, remaining imperfections were filled with automotive body filler, which was rubbed back after curing. The opening in the cab front around the rear of the motor was then enlarged. The body was refitted to the chassis and any binding of wheels was corrected by filing back the offending part. The cab roof was cut from 0.010” brass, curved to shape, then soldered to the cab sides and front. The body now looked like this: Chimney, dome and safety valve were turned from brass bar, as no suitable commercial fittings were either in my scrap box or listed on-line. For these, I used the technique detailed in Ref. 16. A backhead was adapted from one in a spare Airfix City of Truro kit and fitted to the cab. The smokebox door was adapted from a Hornby spare, fitted with a new dart made from a brass handrail knob and phos bronze wire. The splashers inside the cab were tidied up with thin card. Phos bronze handrails and brass knobs were fitted to the boiler. The vacuum ejector pipe was bent up from brass wire and fitted to the driver’s side of the boiler, as shown in the photo of 1043 in Ref. 11. The reversing lever and loco steps were soldered up from offcuts of brass and copper. Buffers, vac pipe, whistles and lamp brackets finished the loco body off. The work plan for the tender was similar to that used for my earlier model of 885, which used part of a Bachmann ROD tender. The tender chassis is a largely unmodified Tri-ang B12 one, with its 16mm wheels replaced by 14mm ones, which lowers it sufficiently. The wheelbase is just right for CR 6-wheeled tenders: The tender body was assembled with reference to this GA, downloaded from the ‘net: The tender body comes from a GBL Director class model, bought for this purpose. It’s not as good as the donor ROD tender used in 885, requiring a lot more adjustment of details – but it was more readily available. The body was cut from the footplate, using the GCR lining as a guide, then a vertical slice was removed from behind the coal space, ensuring that there was enough “meat” left to provide the correct body length. Some details of the tender body were modified to conform more with the GA, then the two halves were re-joined. The coal space didn’t look right, so the shell was gutted and a new coal space was made from thin plastic sheet and glued into position. A new tank filler was made from an old 0.22” calibre shell casing and glued into place. New rear handrails and steps were fitted, together with a fall plate and small tension-lock coupling. Prior to painting, the model looked quite promising: The model was dismantled for painting and all electrical parts were masked. All components were sprayed with grey primer and allowed to dry for 24 hrs. The loco and tender chassis and driving wheels were sprayed matt black. Driving wheel tyres and coupling rods were then wire brushed with a fine Dremel tool. Brush enamel painting then began using Precision Paints pre-1928 green and a selection of Humbrol enamels. Boiler bands were made from thin strips of green PVC insulating tape, pre-painted with Precision Paints pre-1928 green and applied after the loco body’s paint had cured. Glazing, HMRS transfers and home-printed numberplates completed the model. Results 1043 is now well-balanced and can haul a prototypical load easily. She makes a sweet contribution to the small Cambrian lines group of model locos. Here she is, passing some of them at Carmarthen Junction MPD: Reflections A rough calculation of the material costs for this project indicated around A$205 (about GBP124). This amount, spread over several years while accumulating parts and then utilised over the 9-month construction period, is not bad value for money, given the satisfaction it has provided. This has not been an easy build, with lots of new challenges in the bodywork – especially in respect of the coupling rod splashers. The lack of detailed drawings meant that great reliance was made on the few photographs that were available at the time. Still, it provided experience in fabricating some new parts, which developed a few new skills, such as using the metalworking lathe. I’m happy with the result. References and Relevant Links http://www.gwr.org.uk/no440s.html http://www.rmweb.co.uk/community/index.php?/topic/70438-gwr-4-4-0s-on-carmarthen-junction/ http://www.rmweb.co.uk/community/index.php?/topic/110243-earl-cawdor-makeover/ http://www.rmweb.co.uk/community/index.php?/topic/96216-motorise-gbl-city-of-truro/ http://www.rmweb.co.uk/community/index.php?/topic/88895-gwr-ex-cambrian-railways-73-class-0-6-0/ http://www.rmweb.co.uk/community/index.php?/topic/72460-gwr-1331-ex-whitland-cardigan-0-6-0st-project/ http://www.rmweb.co.uk/community/index.php?/topic/67786-gwr-1376-ex-bristol-exeter-0-6-0t-project/ http://www.rmweb.co.uk/community/index.php?/topic/70468-gwr-absorbed-locos-on-carmarthen-junction/ Anon.: “The Locomotives of the Great Western Railway – Part Three – Absorbed Engines, 1854-1921” (RCTS, 1956) Anon.: “The Locomotives of the Great Western Railway – Part Ten– Absorbed Engines,1922-1947” (RCTS, 1966) C.C.Green: “Cambrian Railways Album – 2” (Ian Allan, 1981) R.W.Kidner “The Cambrian Railways” (Oakwood Press, 1954) J.H.Russell: A Pictorial Record of Great Western Absorbed Engines” (OPC,1978) Casserley & Johnson: “ Locomotives at the Grouping – No.4 – Great Western Railway” (Ian Allan, 1966) F.J.Roche & G.G.Templar: “Building Model Locomotives” (Ian Allen, 1968) Guy Williams: “Model Locomotive Construction in 4mm Scale” (Ian Allen, 1979) John Lewis et al: “Great Western Way” (2nd ed., HMRS, 2009) Brian Stephenson (ed.): “Locomotives Illustrated 162 – The Locomotives of the Cambrian and Midland & South West Junction Railways” (RAS Publishing, Jul-Sep 2006) 14 Link to post Share on other sites More sharing options...
outcastjack Posted September 17, 2017 Share Posted September 17, 2017 Great work, thank you for posting. The reference list is especially useful! This is a prototype i really want to model at some point (once I have finally developed the skill needed to make a chassis that runs well). The chimney and dome are excellent! You mentioned you learned a good deal about turning, have you made loco fittings like these before? Failing that how much practice did it take to get right? Link to post Share on other sites More sharing options...
RosiesBoss Posted September 17, 2017 Author Share Posted September 17, 2017 G'day, outcastjack, Thank you for your comments. Over the last year, I have been teaching myself how to turn small items on a midi-sized wood lathe, taking tips from books and Youtube videos. The experience gained here was useful in trying my hand with an old modelmaker's metalworking lathe which I had been given some years ago as a display piece. (I understand that it is around 100 years old.) It had been cosmetically restored, but its main bearings were very worn, so it could not produce anything of acceptable finish. I therefore shimmed the main bearings with offcuts of brass sheet, sharpened the tools, set them to the right height (same techniques as I had learned on the wood lathe) and had a go. Each piece came good on the first attempt. I worked very slowly and carefully, taking about half a day for each item and measuring regularly to ensure I got the dimensions and shapes as close as I could with my limited skills and experience. I think my apprenticeship on the wood lathe was of great help. I was happy with my first serious work on the metalworking lathe. Regards, Rob Link to post Share on other sites More sharing options...
timbowilts Posted September 17, 2017 Share Posted September 17, 2017 Of course one can now take out a mortgage and purchase the Shapeways 3d printed one sold through coast line models :<) Tim T Link to post Share on other sites More sharing options...
coachmann Posted September 17, 2017 Share Posted September 17, 2017 A fair amount of ingenuity was shown with this model. At first I thought, oh no, he's going to try to convert a GCR 'Director' into a small Cambrian 4-4-0. But as your post unfolded I saw you had other ideas after all. Well done and a neat model has resulted. Link to post Share on other sites More sharing options...
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