Dapol's N Gauge Voyager normally comes as a 5-car set where the centre coach contains the motor and 6-pin DCC socket.
Installation of DCC Sound is relatively simple using a CT SL76 in this example, simply plugged in, and a slightly
reduced-height enclosure on the standard CT sugar-cube speaker, mounted above the drive-shaft.
The example here (kindly photographed by David Furniss) employs a neat frame for the speaker to sit on made of shim steel, giving
it good support and keeping it away from moving parts.
David has also used a pair of tiny Tantalum capacitors (the yellow boxes hung off the
back of the motor block) with the SL76 which act as a mini-stay-alive, reducing the sound crackles sometimes present with SL76 installations.