We were a little surprised to discover that this 2017 re-release of Farish's GWR Diesel Railcar was still based on the old
split-chassis model, with no factory-provision for DCC, but it did run well and so made a good candidate for DCC conversion,
starting with a standard (non-sound) decoder, hard-wiring a Zimo MX617.
The chassis block is huge (hence the good running), with the metal right up to the roof, so very little space for even a
Unpick the tape and we find that at least the motor terminals are separated from the chassis, so DCC conversion is a doddle,
Here is the MX617, which we shorten any wires not required (we will not attempt to fit any lighting).
Connect grey and orange decoder wires to the motor terminals, and black and red top the chassis halves.
The decoder is slightly too thick (with it's heat shrink still on) to fit in the roof so we simply snip off a small plastic lug
that protrudes downwards and it frees up just enough height. Very tight though. It might have been better to remove the heat
shrink and replace this with Kapton Tape, but wanted this exercise to be the minimum work required to DCC-fit it. The results
are good - the model runs fantastically on DCC and was converted in just a few minutes.
So, now to convert the same model to DCC sound...
We need to create some space, both for a sound decoder and also for a speaker. Fortunately the chassis is a lump, so there are
various options for removing chunks! Take it all apart and mark out what we will grind away - some off the top for the decoder,
and a chunk from the underneath for the speaker.
The blue speakers are Minnows, and the green one is a Limo6. We eventually decide on a Limo6.
Reassemble the chassis and test-fit the speaker. It will obviously need to be insulated properly from the chassis, but we can
afford it to be very slightly proud of the bottom because the body shell goes lower than the chassis base.
With shortened wires, removed unwanted lighting wires, and recovered with Kapton Tape, the MX648 decoder fits into the recess
that we created on top of the chassis, though we still have to create a little more space up into the roof.
With everything in place, we protect the speaker and disguise it with black tape, refit the body, and check that everything has
enough clearance from the rails.