I don't know of a wiring diagram for that specific model. Here's the RCDR diagram for the one that ERR sells, or used to sell, that's the pinouts of the control board from your set. I am sure this is correct as I've replaced several of those boards with the ERR part. The Trainsounds board is just a horn/bell board, so the wiring should be pretty simple. I also think the pinouts are on the back of the board.
As you can see, the wiring is really very simple, that's not much to connect up.
