I received a Lionel 6-84378 Santa's Choice milk car for Christmas, and I'd like to install an ERR Mini-Commander for operation without needing a special operating track section. But the wiring in the milk car surprised me. Why does it have center-rail rollers in addition to the operating track pickup shoes? Post-war milk cars have just the operating track shoes, and the milk can dispensing mechanism is powered that way. I can't figure out what the center-rail power would be used for.
There are four wires going into the little circuit board inside the car, which looks like a simple rectifier with a 7805 voltage regulator and a large capacitor, presumably to provide DC power to the motor for the mechanism that ejects the cans. Two of the four wires come from the operating track shoes, and two from the center-rail rollers and an outside rail connection on one of the trucks.
Any pointers would be appreciated!
