Make sure both controllers are set to the same polarity (direction switch) and red and black wires are connected to the same terminals on them. Disconnect one of the controllers and see if your train runs. It sounds like something is not wired right (red wire where black wire should be).
need more info. DC, DCC? What loco? What manufacturer? New? Light is lit, no power to motor. motor binding, Motor brushes bad.
im using black wiring an red wiring i have 2 twins and 2 controllers have them all hooked up red on left black on right fire it up and it doesnt work at all the engine light will shine lightly but nothing runs what am i doing wrong?