Auto SW adds a program track output to the Power Cab. Prevents accidental programming of locos on your mainline track when using Program Track mode. Automatically disconnects your main line when in Program Track mode. Does not affect OPS mode programming / Program on Main (POM). Compatible with all DCC systems. One pair of wires in from the Power Cab. One pair of wires out for your mainline. A second pair of wires out for your programming track. Only one output is active at a time. Note: This will not work with the SB5 since the SB5 does not have a program track mode.