Because of the limited space, the speaker has been sliced in half 8 mm from the front face and has been fixed to the rear of the decoder. A 100 uF stay alive capacitor was used to provide continuous sound over dirty track, dead frogs, etc. The whole assembly was then installed into the tender and lead weight was added to restore its original mass. Finally use your controller to set the address of the sound decoder to be the same as its locomotive so that both run together.

When the loco decoder is installed in the locomotive then sound decoder supply can be organised by running a pair of wires from the loco decoder to the tender or by installing pickups off the tender wheels. The photos here show an installation in an old Hornby “Castle” loco which uses the latter method. In this case, the tender had track pickups on one side only so phosphor bronze strips have been used to pick up from the opposite wheels as well.