The short is probably being caused at the frog. If you look closely at the frog you will see a very small area where the rails of opposite polarity come together and they look very close together. They are and some wheels on locos and cars bridge these two rails and cause a momentary short that will stop your train and any other trains running in thst same power district. My club has the same problem on our HO layout as well as me on my N home layout. A simple fix is to paint on a little more insulation using nail polish to extend the insulated area maybe 1/8" back. Apply one coat, let it dry throughly, then apply another coat and let it dry throughly too. Depending on how often you clean your track you will have to the reapply the polish and it does wear off from running your trains. Use Laquere based polish as it is tougher than enamel paint.
I had a problem with this situation when I was using DC control and trains would sometimes stumble going over the Atlas or Peco switches. Switching to DCC made the problem worse with a short circuit occuring there. Nail polish works well and one bottle will (should) last forever.
Last edited by retsignalmtr : 12-17-2016 at 07:47 AM.