How old is that Bachmann unit..?? Might it be that the motor need to be isolated from the frame..?? Check it out with a voltmeter by putting one lead on the metal motor casing, and touch a part of the metal frame with the other. If you get a reading, you'll need to isolate the motor.
Thank you i'll check that out today when i get home. How would i isolate ? tape ? its a plastic body with the disk like motor on the back wheel set. The train body is plastic too the weight looks to be cast also looks to be seperate from the motor.