Each board can handle two outputs with a total load of 1Amp so cab lighting, engine room etc are now an easy possibility. Simple to wire up with a max of 8 wires. GND is a connection you will need to locate either on the decoder itself or the output pin on the socket,(which will vary with pin count of the decoder being used) OUT 3 and OUT 4 should speak for themselves and go with a blue as above to the fed component.
