Steve Johnson Modelmaker
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British D2700-D2707 0-4-0DH
The first batch of D2/1 Class 0-4-0 diesel-hydraulic shunters were built by North British in 1953 for use in Hartlepool Docks. Numbered 11700-11703, they were subsequently re-numbered D2700-D2703. Powered by a 200hp Paxman engine, transmission was a Voith hydraulic unit. When new, they carried the BR Black livery. This was later changed to all over green with some receiving yellow and black chevrons later. The radiator access ladder was removed sometime between the latter two liveries.
The kit is a Judith Edge etched brass kit and it follows Michaels usual construction sequence of separate frames, footplate and body units bolted together. Although I have built the BR version of the locomotive, parts are supplied to build the industrial variants.
I have powered my model using one of Chris Gibbons excellent Roadrunner gearboxes and Mashima 1020 motor. The gear ratio being 54:1, as I want low speed performance from a shunter. The wheels, axles and crankpins are Romford.
Painting is straightforward with a BR Green body, red buffer beams and grey roof. The sprung buffers are a combination of two Gibson types to get the correct stocks and large heads. Extra weight, made from lead sheet, was inserted under the engine casing at the front and between the frames at the rear. There is not a lot of room in this diminutive shunter and these seemed the best places while trying to maintain an even balance. Exactoscale drawhooks and three link couplings are used for cosmetic purposes along with the functional Alex Jackson type coupling. A driver has also been fitted. Transfers are from the Fox Transfers range with Narrow Planet worksplates. This livery had the larger steam type numerals prefixed with a small 'D'.
After a thorough testing and running in, I fitted a DCC decoder. This time, because of limited space within the body, I chose to use a DCC Concepts Zen ZN8H with 'Stay Alive'. This is a very small 'nano' decoder and I managed to fit it between the frames under the cab. The 'stay alive' capacitor unit is placed behind the motor mount inside the engine casing. It is a very tight squeeze! As there is interior detail, I also decided to add a cab light in the form of a pre-wired DCC Concepts nano LED. The decoder only has function outputs for front and rear lights, but fortunately these can be re-mapped to give a different function number and to be active in both directions.
I am quite pleased with this locomotive but am not so sure about the 'stay alive' unit. The reason I fitted it was to try and counteract any stuttering of this short wheelbase shunter over points. I am not after the type that can power the locomotive over yards of paper towel on the track, just to smooth out a stutter for a fraction of a second, which it doesn't seem to do. Again I have observed that when the loco does stall, it pauses for a fraction of a second before the 'stay alive' kicks in and then promptly sends the loco in the reverse direction at full speed for a second or so! Reconfiguring the decoder to DCC operation only seems to cure this surging. I don't think the 'stay alive' on this manufacturers decoder is doing the job I wanted and various comments on the internet seem to back up my observations. For future builds, I will investigate alternative offerings.