I just set up my son's track which we had put away for a few months. The set up is pretty simple, using 4 switches (3 rights and a left). It is the oval sample shown on the switch boxes with one siding and one cross over through the middle. I apologize if my terms are incorrect. The engine runs fine by itself through the whole layout but when cars are hooked to it the engine loses power when it hits a section between two particular switches. It runs fine with cars attached through the rest of the layout. I have checked and rechecked the connections and just can't figure it out. As I noted, the engine runs fine by itself (with tender). Two of the cars, the caboose and a flat bed car, draw electricity to light lights, other than that none of the cars being pulled draw electricity from the track. Is it more likely a problem with one of those cars or possibly one of the switches? Any guidance would be appreciated.