I have a stand alone siding. On each end, I have a half straight track with an insulator pin in the center rail, and a lighted bumper (always on) powered by a direct center rail feed to each half track.
In the center of the siding, I have a Lionel Fish car, with a switched power feed, and a ground.
The Fish car is noisy, so I decided to use a rectifier to see how DC would affect the situation. I wired the switched power feed and the ground through the rectifier, not touching the lighted bumper connections. That means the bumpers have an AC power line, and a DC ground.
Here's what happens: When the Fish car is switched off, the bumpers are illuminated, but when I switch on the Fish car, it works fine, but the bumper lights go off.
Thanks as always.