Using a Radio Shack plastic project box, I installed four ON/OFF toggle switches to it with a "hot" wire from the main transformer to a terminal block, then to each switch, and then to the isolated center rail of each siding. I placed a lighted bumper at the end of each siding as an "indicator light" to show whether a siding was powered (or not) according to the position of the switch. Low tech, but it works for me!
Mike Mottler LCCA 12394