You can pretty much guess the connections. It a small mainboard with two very small daughter boards.
A wire to IR sensor for chuff trigger. A wire to smoke unit. A wire to head light.
Track Hot and common in. Two wires to the coupler \tender for speaker output. Two wires to motor.
It's so small, you need a board guru to do component level repairs. I am not sure if you could get a board schematic. Ask Santa Fe Fan. All he can say is no.