When the driver wheels are always at 2 positions when stopped, the engine will stall, i.e., when I turn the transformer on the engine seems not to be getting current - the engine light stays off, the motor makes no sound, & the it fails to move, unless given a bit of a push -it then runs normally (until stopped). The track is getting current since the coaches' lights go on as soon as I give it juice from the transformer. Again, once the train is moving it runs ok. Also, if the wheels are not at the 2 certain positions when stopped, the engine starts normally. (Tracks & wheels have been cleaned.)
Any thoughts Mr Bach-mann? or anyone?
I'd say to pick up a cheap digital voltmeter (Harbor Freight has one that's usually on sale for under $5, and they had a coupon for it for FREE out a while back in the Sunday coupons) and use it to check the tops of the drivers, or anywhere else you can easily probe, to see if it's getting power. I know these can be a bear to take apart, so I'd examime where the power goes from the wheels into the locomotive carefully. Make sure it's not related to the drivng rod position or something. (I sold mine quite a while ago, so I'm not 100% on how the power goes up into the motor).
My take - you have a mechanical bind in the drive train. It may be with one of the drivers or it may be in the gearing between the geared driver and the motor.
-John