I wanted to make a shunter for my 009/H0e model railway that looked ‘chunkier’ than the one described in Railway Modeller using the Kato 105 chassis. This conversion, to me, looked wrong because the Knightwing body had to be shortened by 2 grill bays.
I looked at using the Graham Farish Class 08 n-gauge outside-framed shunter chassis so as to have working conrods but, instead, I decided that it may be possible to use the Graham Farish Class 14 n-gauge inside-framed shunter chassis instead as this was, at 61mm, longer and also had the benefit of having working conrods.
I wanted to run this loco using DCC and so I had to fit a Digitrax DZ125 decoder to the chassis.
This presented a few minor problems to be solved. The Farish chassis is live and connected to one set of wheel pickups.
To fit DCC you must isolate the motor completely from the chassis. Farish connect to the chassis using a copper strip screwed to the chassis which is then trapped against the PCB at the rear of the motor by a ‘pin’ cast as part of the chassis block.
This ‘pin’ has to be removed. For this task I used a burr in my Dremel drill, carefully grinding the pin.and overlying copper strip, away whilst leaving enough copper to enable me to solder the black wire from the DZ125 to it.
At this time I used my solder rework station’s hot air gun to remove the surface mount resistors that were on the circuit board. This completely isolates the motor inputs from each other.
After de-soldering the existing yellow motor wire you can then solder the DCC decoder to the chassis contact (decoder black wire), the already installed yellow former motor wire (decoder red wire), and the PCB motor contacts (decoder grey and yellow wires).
That completes the chassis modifications. An hour on the rolling road ran the chassis in nicely.