How to convert N Gauge Graham Farish Class 37 (Poole) to DCC

This guide covers the following models:

• Class 37 D6736 in BR green livery (8014)
• Class 37 37035 in BR blue livery (8015)
• Class 37 37408 'Loch Rannoch' in BR blue livery (8035)
• Class 37 37699 in Railfreight Coal Sector livery (8036)
• Class 37 37887 in Railfreight Petroleum Sector livery (8037)
• Class 37 37906 in Railfreight Metals Sector livery (8038)
• Class 37 37055 'Rail Celebrity' in Mainline blue livery (803D)
• Class 37 37408 'Loch Rannoch' in EWS Red & Gold livery (803E)

This guide is for the Poole made chassis. For the China made chassis, follow Chinese split chassis conversion method.

Step 1 - Remove Body

Remove body by pushing upwards.

Remove the underfloor battery box.

Step 2 - Remove Bogies

Remove the bogies by removing the screws holding the black retainer clips

Remove the two long screws that go through the top of the chassis, with nuts underneath

Step 3 - Isolate Upper Motor Contact

Remove the motor brush clip, brush spring, capacitor and the copper strip.

Remove the middle sections of the copper strip, so the outer parts have a clear gap to the middle part. The middle part is retained to ensure correct spacing between the brush sleeve and the commutator.

Refit the motor brush spring and clip, and the two long screws. Add some solder to the two outer contact strips, and the brush clip ready for adding the decoder wires.

Step 4 - Isolate Lower Motor Contact

Turn upside down, and remove the lower brush clip, spring and sleeve.

Replace the sleeve with a plastic digihat.

Refit the spring. Add shrink sleeving to the legs of the brush clip, and add some solder to the top.

Step 5 - Connect Decoder

Drill and trap a hole into the top of the chassis, and screw a solder tab to it. Add some solder to the top.

Fix the decoder in place.

Add a black link wire between the two contact strips.

Pass the grey decoder wire down through the chassis and solder it to the lower motor brush clip.

Solder the black decoder wire to one of the contact strips alongside the black link wire.

Solder the red decoder wire to the chassis solder tab.

Solder the orange decoder wire to the upper motor brush clip.

Step 6 - Refit Body

Refit the body and battery box, and the conversion is complete