I posted this on the NGRM Forum; for the benefit of those not on there, I repeat it here:
The excellent work done by several members, using the Minitrains F&C Chassis has provoked me to do something with the one I purchased a while ago. I know I could wait for NP to come up with something, but I am impatient, and have been inspired by these other projects! ;)
Rather than go down the line of an 0-4-0, I wanted something different. It is generally accepted that to make an 0-4-2 is difficult, because of the position of the motor, well back on the mechanism; so, how about a 2-4-0?
Browsing through my library of books, I was reminded of the former Plynlimon and Hafan Tramway loco TALYBONT, which later was used in construction of the Vale of Rheidol, and became RHEIDOL on that line.
RHEIDOL (I will use that name) was built by Bagnall in 1896, new for the P&HT, which was built to the gauge of 2' 3", which makes it ideal for 009! It had a short life at the P&H, and was snapped up by the contractors to VoR and converted to 1' 11 1/2" gauge for use between Aberystwyth and Devils Bridge. As mentioned, it was a 2-4-0T, and ran for a while with spark arrestor chimney, both at Hafan, and Aberystwyth. It was scrapped by the GWR around the time that they provided the three new 2-6-2 locos.
My sources of information include C C Green's book on the line, Boyd's Narrow Gauge Railways in Mid Wales, and various booklets. Unfortunately, there are no pictures on the internet, that are out of copyright to show here. Taking the drawing from my copy of Boyd, scanning and printing to 4mm scale, I realised that the dimension from front driving axle to the rear of the F&C mechanism was spot on for RHEIDOL. However, the F&C wheelbase, at 16mm is some 4mm short of the 5 ft of the prototype. I am happy to live with this discrepancy. The other major challenge is that the connecting rods drive on to the front axle, not the rear, as the model mechanism. I can think of two solutions to this: remove the crankpins, and refit the longer ones, plus washer and connecting rods to the front wheels; or dismantle the keeper plate, and exchange the wheels. Although I believe that James has followed the first path in his diesel conversion, I chose the latter course. Before doing this, I would strongly advise unscrewing the plastic mounting block for the pick-ups, which also serves as the female part for the mounting clip. With the keeper plate removed, swap the axles, taking care not to disturb the multitude of small gears (note: do as I say, not as I did! ;) ) Whilst the keeper plate was removed, I cut this short at the front, to the point of the front of the mechanism. This view shows the underside, once the keeper had been replaced.
(https://elmgatemodels.files.wordpress.com/2014/11/underside.jpg)
With the connecting rods now driving onto the front, the cylinders are moved forward, of course. I made up an extension piece, from plastic card, to mount the cylinders in the correct position. This fortunately corresponded with the position of RHEIDOL's cylinders. In the above and below views, the cylinders are temporarily secured by a M2 bolt and nut. The rear of the extension piece is secured by the nylon screw provided with the mechanism (and which is intended to secure the cylinders until they are fastened by the chimney into the body).
(https://elmgatemodels.files.wordpress.com/2014/11/above.jpg)
Not clear from either of these views is the leading pony truck fixing arrangement. The truck was assembled from a spare pony wheel (I believe from the Minitrix 2-6-2 mechanism) fitted into one of RT Models' etched NS pony trucks. The pivot hole was opened out slightly to take the M2 screw, and a "U" shaped cavity formed beneath the extension plate, so that the truck could swing freely, whilst the extension is firmly fixed to the mechanism. The central "spine" of this extension is narrow enough to permit the finished chassis to negotiate 9" radius reverse points, if required. The footplate was cut to fit around the various parts of the chassis. The turret in front of the motor contains the mounting clip, supplied with the chassis, and the two screws fastening this can just be seen protruding. With a little weight on the front, the finished article was thoroughly tested around Artmouth Cove, including the said 9" reverse curves, and the steep gradient down to the Fish quay. I was happy with these tests, so carried on to the next stage.
The scale boiler diameter is 11mm, and I happened to have a length of steel rod, just over this dimension. I turned this down in my lathe and cut it short enough to fit from front of smokebox to where I reckon the fiebox is situated in the cab. A slice was taken out to fit over the fixing turret, and the smokebox formed of 20 thou wrapper and 30 thou front. Once drilled for the cylinder fixing screw, it was possible to screw the parts together, using a spare chimney from the Minitrains Koppel (first generation). This had to be turned down to fit into the height of the smokebox. A suitable 10mm diameter smokebox door, and a dome from my spares box appeared to be a good match for that on RHEIDOL, and was positioned using the scale drawing. The footplate has been cut to scale length, and a 10 thou top plate added on top of this. The front buffer beam has been added. Here she is, posed in front of the drawing -
(https://elmgatemodels.files.wordpress.com/2014/11/stage-1-with-drawing.jpg)
After further testing, a ballon chimney, from the Varikit parts, was adapted to fit the Minitrains chimney. The new chimney was drilled 2mm through, and the lower section sliced off horizontally. The hole in this was opened out to be a free fit for the fastening screw. Further surgery to the Minitrains chimney saw the balloon section removed, and the remainder again turned down to 2mm. This was then low-melt soldered into the top part of the new chimney. The chimney now acts exactly as the original, and fastens the front to the body, through the cylinder moulding, into an M2 nut beneath.
(https://elmgatemodels.files.wordpress.com/2014/11/stage-2.jpg)
Finally beginning to look like the prototype, this is where I have reached at present. I will continue soon....