DC Blocks with Potentiometer control.

[AyTrane]

I have always had a DC layout in one form or another. My new layout is wired in blocks, but I was wondering if it would be possible to control one of my two mainlines with a potentiometer to control the current going to the engine? If I want to run a freight train on the inside loop, it usually runs a lot slower than the passenger train on the outside loop. I want to control the speed of the outside loop individually from the inside loop, but have them on the same transformer as I sometimes switch the trains from inside loop to outside, and vise versa.

I've asked a couple electrical engineers about the matter and all they have been able to tell me is that is could work in theory and not damage the transformer. Anyone have experience or advice? Thanks,

Adam

 

[UP2CSX]

Adam, I really don't understand what you're trying to accomplish. If you're running two different trains on DC with one powerpack, one will always run slower than the other because the other motor will draw more voltage unless you have two absolutely identical motors pulling the same load. A potentiometer will make no difference since you can't feed more voltage through the pot than what's already coming out of the one power pack. You need two powerpacks or one power pack with two throttles. A powerpack is just a variable rheostat, which is a form of potentiometer. With two power packs, you can control the trains speeds individually by cranking up the throttle on the slower one. I've never seen a multiple train layout on DC work without one powerpack for each train you're running.

If you start adding up the cost of powerpacks, wiring, toggle switches, and control panels, you could probably pay for something like a Digitrax stater set and do away with all the complications of blocks and having to throw toggle switches as the different trains move to different parts of the layout. As has been said, with DC, you run the layout. With DCC, you run the trains. Your choice but you need two power packs at the very least if you're going to stay with DCC.