Thanks Stan,
I didn't consider the 0 ohms scenario. I plan on giving these to my son. These are a late 70's, early 80's set of Williams kit cars I put together for him when he was a young boy. I plan on giving them to him when he's ready to put up his own Christmas display. He's graduating college next week for the second time so hopefully the time is close. I've upgraded the trucks and couplers, added vista domes to all of the coaches and observation car, now the illumination. I probably could have bought him a new set of cars for what the upgrades cost but it's more of a sentimental thing for both of us. It's pulled by a set of MTH ABA PA's that I repainted. The numbers on the A units are his birthday, the B unit is mine. Nowhere near prototypical but they mean something to him.
I like your idea of having two separate fixed resistors that can be switched in and out of the circuit to change light intensity for day/night running. This way I'm not building in a potential self destruct mechanism by turning the pot in the wrong direction. Thanks again.
