I don't know if this helps, but I recently got an M1000 set. Now here's the kicker, the wiring was backwards somewhere in the system of cars. It's 4 pin connector, the center two wire are 3rd rail and ground, the outer two powered the rear motor. Somehow somebody replaced a cable and it was wired such a way the keyed plugs were soldered backwards wiring thus shorting the rear pickup and frame and reversing the motor direction thus fighting the engine. Just wondering if somehow you too have a mismatched system with a railcar and the motor is fighting the engine up front.
A check is to plug the tail car directly into the engine, Caution, check for shorting or current draw on track power up. If that passes, lift the rear truck and try to get the engine to spin and see if this reversed motor syndrome is hitting you too? Wondering how many of these are miswired and or get mismatched sets.
