Advertised as doc on board and says that on bottom of loco. Don't see anything in gears...thinking mechanical problem is ruled out due to running a few inches each time it's powered on.

Hi-

Purchased a new n-scale set-up for my son for Christmas. Bachmann n-scale ez-track with an existing EZ Command DCC controller.

Newly purchased locos are EMD GP7 DCC on-board and ALCO 2-6-0 DCC on-board.

ALCO functions fine, but the EMD is not working properly. Whenever the controller is powered on, the EMD moves forward about 3-6 inches and stops and there is a constant humming sound. Will not respond to DCC control ( no movement, lights, etc..) on default ch3 or accept programming to any other channel.

Would appreciate any idea.

Thanks