The making of Dennis

The Snailbeach  Railways wasn’t exactly flush with locomotives – it only ever owned 6 throughout its 80 odd year history. The longest lived was its first - a second hand cast-off 0-4-2ST from a colliery named Belmont – of which there are no surviving photos. If there was a loco which is synonymous with the SDR its the third loco Dennis, this was purchased new from Bagnall in 1906 and named after Sir Henry Dennis the SDR’s Engineer and Director. It was an 0-6-0T of monumental proportions for 2’4” gauge; Dennis’ size tells us that the SDR thought it had more in common with its 2’6” gauge near neighbour at Welshpool, than the 2’ gauge railways of North Wales. 

Dennis was a direct replacement for the SDR’s second loco Fernhill a Scottish made 0-6-0ST of similar size showing that there was a clear purchasing policy for hefty locos. When Fernhill was bought in 1881 traffic was heavy in both directions (smelted lead trains of 100t downhill) and similar amounts of coal for the mines and smelter back up grade. By the time Dennis came along however, the up grade traffic was dwindling, and quarry products were surpassing lead ores as the main mineral traffic. The size of these loco’s appears to have been mainly required for downhill braking effort on unfitted (i.e. no continuous train brake) mineral trains.

Dennis had a short but brutal working life with very little maintenance, by 1920 she was out of service, and horses worked the empties back up hill for the final year of the old company. Disassembled for a major overhaul when Col Stephens bought the railway in 1923, the work was never completed and she was eventually scrapped in the 1930s. 1920s photos of the partly disassembled loco next to the Snailbeach shed show how much bigger she was than the reguaged 2’ gauge locos Col Stephens bought to re-power the line. 

The model

A 00 scale (1:76) white metal kit for Dennis has been around since the 1960s made by GEM - the range is currently sold by Lytchett Manor Models but are definitely beginning to look a bit dated. Typical of early 009 kits this required an N gauge donor chassis to complete – in this case from a Graham Farish Pannier tank. The chassis is reasonably close in terms of wheelbase, but is of course inside framed. 

I purchased a part complete Dennis kit for my first attempt at building part of the Snailbeach in the early 1990s; it must have been at least 10 years old even at that point. The early Farish chassis either run well – or they don’t; with no apparent reason for the difference. Some say its all in the motor brush spring pressure – who knows; I got a good one.

Despite the fact it ran reasonably well, the inside frames just looked horrible on what was supposed to be an outside framed loco. So when I started thinking about having a second go at modelling the Snailbeach rebuilding Dennis to a more prototypical appearance ended up being the catalyst for the whole project.

For a start I ordered up a set of BR class 08 shunter wheels from Graham Farish’s spares department (by now part of the Bachmann group). These have a much finer wheel standard than the 1980s era models, and have plastic axle and crank extensions for outside frames; this makes the modern 08 chassis a go to source for 009 steam loco mechanisms.  The wheelset comes assembled and is not a direct replacement for the old pannier tank one - the connecting rods need to be swapped, and the main drive gear on the centre axle is different (a smaller nylon spur gear on the modern 08, whereas its a brass worm gear on the 1980s pannier chassis). Swapping the rods was straightforward enough, but the gear was a more technical challenge. 

The nylon spur gear on the modern wheelset is off-set and supported by an central boss cast into the axle, this had to be removed to make room for the brass worm gear to fit. To do this I used a gear puller to remove one wheel and then the nylon gear. Next I placed the wheelset in a mini-drill to make an improvised lathe and “turned” the boss off with a jeweller's file. I then carefully tapped the brass worm gear into place, and reassembled the wheelset using a quartering tool.

The chassis then needed a set of dummy outside frames. I fabricated these out of styrene sheet and glued them to the chassis block with CA.

Power for the wheels

The old style Farish chassis are nearly impossible to convert to DCC due to the bottom motor brush being integral with the frame (and yes there are ways to do them, but the results aren’t always good). Instead I thought I would experiment with “dead rail” – that is no power to the rails but on-board battery power with radio control. I thought this might improve slow running – as rail pickup is usually the problem at slow speeds in smaller scales. Li-po batteries and r/c receivers are now small enough to make this possible even in such a small scale. I initially set Dennis up with a DT (DelTang) Rx63 r/c receiver and 9v inverter to boost the 3.7v output of the single re-chargeable battery to a voltage suitable for the motor. 

The boards are not difficult to wire in, but a certain amount of reading is required first. I found the UK based Micron RC website very helpful.  I tested this installation a few times - operation was slow and smooth, but I found that even with the largest Li-po battery (70mAH 50C) I could get inside the model, there was only 15-20 minutes run time. This may well have been improved with a modern low resistance motor drawing less current or requiring a lower voltage than the old 3 pole open frame type. A second battery pack running in tandem would have also lengthened run time – possible in HO or larger scales but not in 009. I removed the r/c gear and reverted to conventional 12v DC analogue control via the rails. This decision meant that Pontesbury Sidings was to be my first conventional analogue layout I have built in 20 years.

With a body to match

The whitemetal body kit was entirely disassembled, and stripped of various layers of previous paint, the parts cleaned of glue, filed for a better fit then re-assembled with CA. Parts of inside of the kit under the boiler and tanks were trimmed back to make way for the r/c gear. Even with this metal gone the kit remains very heavy for this scale, so no problems with tractive effort here! 

I replaced the cab roof with a new one fabricated from brass sheet, installed “turned” cylinder lubricators and fabricated injectors with control rods. Where areas of rivet detail had been damaged due to paint removal I added this back in with Archer 3D decals. The body then got a coat of primer, followed by an apple green colour (mixed from Revell and Tamiya paints) on the cab, tanks and boiler, red buffer beams and black smoke box and below the running plate. The tanks and cab got a squirt of gloss varnish, and then Fox Transfers lining decals were installed. I always use Microscale Micro Sol to settle decals it melts them onto the surface and providing they are on a shiny surface gets rid of any film silvering. 

Once dry I gave the body a coat of Testors Dullcoat (I won’t use any other matte clear varnish), then I added hand rails, and etched maker's and name plates by Narrow Planet. The final steps were a driver figure (Masterpiece by Falcon Figures – the manufacturer doesn't have website but you can get them here, or direct from the manufacturer at UK shows or mail order) and some weathering using Lifecolor pigments and inks.