The receiver board, AKA the radio board, AKA R4LC is the board that listens to the signals from the command base and translates them into loco commands, like go, stop, forward, reverse, speed, coupler commands, smoke on/off, horn, bell, and the like.
The railsounds board has the recordings of the loco sounds on it (horn/whistle/bell/chuff/prime mover).
The power supply board provides power to the railsounds board.
The mother board holds the smaller boards and provides interconnections between them.
