Bought two Bachmann 47 a few months back, tested them and both seem to have a "wobble" at one cabin end, when running. One of the locos seems to only do this in one direction and the other in both directions.
I'm running it on track on a hard floor, so there isn't anything to absorb vibrations. The track is flat (obviously) so i'm not sure if this is expected, or whether its something with the bogie?
I can only describe it as horizontal and vertical movement of the cabin, in addition to the loco's direction of travel.
Not sure whether to ask Bachmann to take a look as they're under warranty.