Steve Johnson Modelmaker
Walker Brothers F501 Class
F Class Model Complete
A short video showing the F Class on my test track
Picture courtesy of Colour-Rail
As part of the modernisation programme on the West Clare Section, CIÉ ordered three diesel mechanical locomotives from Walker Brothers of Wigan. Walker Brothers had supplied a number of narrow gauge units to various Irish railways over the years, particularly the County Donegal and Clogher Valley. The West Clare also had some railcars as part of the modernisation, based on and very similar to the two County Donegal railcars 19 and 20. Delivered in 1955, these 3ft gauge 0-4-0 + 0-4-0DM centre cab locomotives were fitted with two Gardner engines of 224hp, which were fitted under each bonnet. The drive was a mechanical type by Hardy Spicer, with each engine driving the opposite bogie. The bogie units had four 2ft 3in diameter wheels and were coupled to form the 0-4-0 unit. With a maximum speed of 25mph, an overdrive unit allowed them to reach 32mph on passenger trains. The original fleet numbers were C31-C33, the 'C' suffix being applied to all West Clare stock. However, this conflicted with an order from Metropolitan Vickers, so the numbers were changed to F501-F503. The modernisation didn't save the West Clare, although it was the last narrow gauge railway to operate in the Republic. The locomotives were withdrawn with the closure of the railway in 1961. They lurked about at Inchicore for some time, rumour being that Bord na Móna might purchase them for their 3ft system. However, this was always highly unlikely as the locomotives weighed in at 23 tons, the limit on Bord na Móna being 10 tons. However, some of the railcar trailers did go to Bord na Móna. The Isle of Man tried to buy the locomotives, but their offer did not meet CIÉ's expectations. With no takers, the locomotives were finally cut up in 1968.
The Model at a very early stage of construction
So, to the model. Well, Allen Doherty of Worsley Works has produced an etched brass body kit in 4mm scale. The locomotive is sold as a 'Scratch Aid' kit. So don't expect any fancy instructions or any of the bits and pieces you would get with other locomotive kits, this is just a body etch. Not that there is anything wrong with this, but this sort of kit does take a bit more work and may not be what you are expecting. However, having said that, the etch is nice and clean and is very straightforward to assemble. Once the parts have been carefully cut out from the fret, they can be soldered or glued together. I chose to solder mine. The parts included are the mainframe, the two bonnets, two cab fronts, sides and roof, radiator grilles, side valances and buffer beams. The bonnets have to be rolled to match the radiator profiles. This is made easier by the thoughtful provision of some finely etched lines on the other side of the etch. Assembly is pretty obvious, although I chose to leave out the two strengthening etches from under the bonnet. I did this to facilitate the drive mechanism. Curiously, the cab roof didn't fit very well, it was too small. I don't know if this is me or the kit. However, I made a new one from some plasticard. Other parts are required to finish the body.
Having assembled the body, you will notice that there are a number of small etched holes for the various handrails. I used Alan Gibson's 0.33mm brass wire for these. There are two exhaust pipes visible. Looking at the front of the loco, they are on the right hand side between the right and centre cab windows. I used some 1/16" brass tube for these. On the opposite side at the top is the air horn. These are quite short and I used a cut down two brass ones from Howe's of Oxford. The bonnet fronts are adorned with a headlight. I found that RT Models make small cast white metal headlights (4LNP001) that seemed a close match. Further down, just inside of the lower handrail fixings are two marker lights. I carefully drilled some holes and inserted a brass lace making pin suitably cut to length to represent the lens. The middle bottom of the bonnet is the where the brake hose emerges. I used some of the white metal type from MJT. Moving down, we come to the couplings. These locomotives were fitted with the so called Chopper Couplings. I have used some of the nickel-silver versions from Branchlines. They are not quite the right pattern as the 'buffer' is round, whereas the West Clare type seem to be rectangular. To the right of these is a small two rung ladder. I used some spare from a signal kit.
On to the bodysides. Sticking with the front, the radiator housing has a filler pipe sticking out at an angle about halfway up. A piece of brass tube inserted into a suitable hole solves this with a pin head as the cap. Moving further down, don't forget the cab door handle. Below the cab, we have the fuel tank behind a another ladder. A piece of spare brass suitably shaped will act as a fuel tank. The body is painted green with black handrails and red buffer beam. The numbers are positioned to the right of the cab door and are gold. When the body is complete, glazing can take place. A single arm windscreen wiper is fitted to the bottom of the centre window.
Now on to the chassis. When I started to build the body around 1996, Mike Chinnery made some ready to run bogies for this loco. Unfortunately, I left it far too late to get some and Mike has since stopped doing these. However, back to the present (2016) and the ever helpful folk on NGRM-Online pointed me in the direction of Malcolm Savage who supplies the bogie castings and etches. All that is needed are the wheels, motors and gears, available from Branchlines. So, I have now obtained the castings and motors etc. and will shortly start assembling these units!
Bogie castings and etchings
Initial bogie construction
The reduction gear from motor to layshaft gives a ratio of 2.37:1 while the layshaft to axles gives a further reduction of 14:1. This gives an overall ration of 33:1, which should give some reasonable slow running. The layshaft to axle gears are the trusty Tenshodo 'Spud' type.
Bogie with motor and pivot fitted
A bit more work on the bogies saw them completed. This involved adding a flywheel (Branchlines 4 x 12mm) to smooth out the motor. A tidy up of the pick up wires and fitting of the sideframes. The cranks are laminated in two parts and these were soldered together before carefully fitting on the ends of the axle extensions. Quartering was necessary here before firmly attaching them with a dab of Loctite to secure them. The connecting rods were then fettled by carefully easing out the holes to make sure there was no binding. When I was satisfied with the running, the cranks and rods were painted red. I'm not sure if they were ever red in real life as the only photographs I have seen show them a very dirty black. A coat of varnish finished the bogie off.
The completed bogies
The bogies spent a period running in and I noticed that one bogie was slower than the other. I thought this might be a bit of tightness that further running might cure, but it didn't. I had another look at the 'slow' bogie, partially taking it apart to see if I could make it run faster. Despite my efforts, it was still slow, so I can only conclude that it is the motor running at a different speed. It doesn't look very good with the unit moving and one bogie noticeably going slower, so a cure had to be found. I opted to fit a 100 Ohm surface mount variable resistor in series with the 'fast' motor. By carefully altering the resistance, I eventually got both bogies to run at the same speed.
The next job is to make a frame to hold both bogies and fix to the body. This was done by cutting a piece of brass strip and drilling two holes into it at the correct bogie spacing. A screw and washer secure the bogies to the strip. Another piece of brass was folded and soldered in the centre of the brass strip. Two 'legs' were made in this strip that rest on the underside of the body's frame. Holes were drilled in this and two nuts were soldered to the inside top of the frame. This secures the bogies to the body.
Having now done the major body items, the body was cleaned up and primed. A few areas need a tidy up a and provision needs to be made for the 'chopper' couplings.
The next job was to find a suitable shade of green to paint the body with. This is easier said than done as no commercial railway colour is available. Two shades appear to have been used on CIÉ green loco's, the F Class seem to use the lighter shade, but colour photo's show this as quite faded and probably not accurate. Despite seeking help from 'Irish railway modelling experts', nothing was forthcoming. However, the larger mainline diesels did use a shade very similar to Southern Railway post-war Malachite Green. So, in the absence of any other information, I painted the locomotive in this shade. Number transfers were FG1305 gold Cheltenham Medium from Fox Transfers. With these applied, varnishing was carried out using Phoenix-Precision satin varnish (PAV72). Glazing the cab with clear acetate completed the model.
Personally, I am very pleased with the result and it completes my collection of CIÉ diesel locomotives.