The inspiration for this project was my need to make models of the products built by the locomotive builders of Leeds and for this project my attention turned to John Fowler. I decided to build two Fowlers side by side, one live steam and one battery.
No25 is based on the locomotives suppled to the East Africa Railway.
An internet search turned up some good photographs and a sketchy general arrangement. Enough to make a start.
The Chassis
For this project I decided to use a commercially available chassis to save time. One difficulty is the Fowler side rod drive used on the prototype, where the jackshaft is elevated and the connecting rod joins the coupling rod with a raised knuckle joint. No such chassis is available. Perusal of the Roundhouse website seemed to indicate the Harlech Castle chassis kit would be adaptable for my needs. The chassis is slightly too short if making the model exactly to scale, but as the prototype is large 2’6” prototype I rescaled the model to suit 2’ gauge. The chassis needed modification, so the jackshaft holes in the side frames were blanked off with soldered in plugs. New holes were marked off and drilled higher up and the Roundhouse axle brass bushes fitted.
Underside view of the assembled chassis, much as intended by Roundhouse except for the elevated jackshaft.
To make the coupling rod with the raised knuckle a triangular piece of 1/8” gauge plate was cut and silver soldered to the top of the Roundhouse coupling rod, then shaped and drilled. The Roundhouse connecting rods were unsuitable so new connecting rods were made from the same gauge plate and fitted.
after soldering on extra plate to form the raised knuckle the coupling rod were bolted together to profile the road and drill the crank pin hole.
The chassis was fully assembled as per Roundhouse instructions. Testing was carried out with a jury-rigged battery and radio control, and the chassis run-in.
Running Board.
A piece of 28thou nickel silver sheet was cut to size to form the footplate which was drilled to pick up the Roundhouse mounting holes. Two brass angle sections were soldered to the sides to form the valances. Cab steps were fabricated and soldered to the running board valances. The Roundhouse buffer beams had unwanted holes and cut-outs therefore new ones were made from 2mm steel plate. Gusset angle plates were folded up and mounted to replicate the visible ones on the prototype. Coupling drag boxes were made from nickel silver sheet and mounted to the new buffer beams.
Cab
The cab presented a few problems. The cab corners have large radii and the windows are sloping parallelograms with radius corners. I decided to make the cab in quarters with the joint in the middle of the sides. The corner radius was folded in using a 4mm rod in the folder, this produced a clean, uniform radius. Each of the two halves were soft soldered back-to-back, and the cab windows and roof profile cut out and shaped.
Two halves of the cab front soldered together front to front to file the sloping window apertures. They were resoldered side to side to form the cab opening profile
This was repeated for the rear halves. The four sections were soldered up onto a base and stiffeners across the cab openings added. The roof was rolled in two halves with the tight edge radius folded in with a 4mm rod in the folder. Rivet details were added using real rivets soldered on. Air receivers, control desk, floor and tool box were made and added.
Fully soldered up cab assembly
Bonnet
Fowlers certainly don’t make thing easy because the bonnet sides slope inwards, the bonnet top has a compound curve, the front also slopes inwards, is curved and the top blends into the side and top with large radius curves. The bonnet front has nine large shaped apertures and the side panels have two rectangular apertures.
The bonnet is made in three parts. For the bonnet top two pieces were cut to the cross-section profile of the bonnet top cross section. These were soldered to the ends of four brass angles to the correct length to form the bonnet top frame. A piece of nickel silver sheet was cut to size, rolled to the correct profile and soldered to the frame forming the top panel. Exhaust and fuel filler cap details were made and fitted.
Bonnet top assembly
The side panels were sheared to size, soldered together and the apertures cut out and shaped. These were de-soldered and soldered to the bonnet frame. This gives the slightly irregular appearance of real panels. Fine stainless mesh was soldered to the inside of the bonnet apertures.
Side panels, one stack of soldered together, drilled and ready to file. Four panels with finished apertures
Next a piece of nickel silver was cut and formed by rolling and folding to the correct shape for the bonnet front. This was soldered to a third plate cut to the bonnet cross-section profile.
The nine apertures were carefully marked out and delicately cut out with a Dremel and burr. This was probably the most time-consuming part of the project. It has to look right because it is a highly visible and distinctive feature of Fowler diesels.
The final piece was the front top section with all those compound curves. Three pieces of brass rectangular section were soldered together. This was placed on the assembled bonnet and the top curve and front curves marked with a Sharpie. The belt sander brought this down to size and finished filed to shape.
The integral light was through drilled for a 3mm LED and a 4mm stainless steel washer soldered on for the bezel. Handrails were made from 1.8mm TIG welding wire and Roundhouse knobs.
Bonnet front panel and bonnet front top.
Assembly
The bonnet and cab were bolted to the footboard using 2mm screws to the running board which in turn was bolted to the chassis using the existing Roundhouse mounting. Batteries were mounted over the motor on a bracket and the Micron RC mounted on top of these. The roof is mounted with four brackets and four 2mm screws under the roof lip.
First trial assembly of bonnet and cab sub-assemblies onto the footplate
Detailing and Finishing
Being open cab this was detailed, but not having any photographs of the actual controls the ones made were based on a 410-class locomotive.
Before finishing the controls, I turned up a Fowler brochure with a line drawing of the correct control layout. This will be dealt with later.
The battery pack was mounted on a frame over the motor and the Tx mounted above this. LED lights were fitted; the front one in the integral fitting in the bonnet; the rear one fitted into a housing formed on a doming block.
Painted and awaiting radiator nameplates
