Just enough space in this lovely model to fit Zimo MX648 sound decoder and SugarCube7 speaker, to great effect...
Remove body, revealing 6pin socket
Take out socket board and plastic mount to make space for decoder and speaker. Also removed pair of supression capacitors hidden beneath motor.
The Decoder is fitted on top of the gear housing, which was filed a little flatter to give a more stable fit and also a tad more clearance from the top of the body.
Neatly placed MX648 and SugarCube7 in the created space.
Photos courtesy of Ivan Gale