I have a tight curve on my layout and a DMU set that can't make it. The coach with the motor gets round okay, but not the coach it's pulling. I suspect adding some weight to the lighter coach might help. Any thoughts, on the sense of this approach and on how best to do it?
Hi;
Have you tried pushing just the offending coach round with just finger power or a short stick to see if it still lifts off?
It sounds as if the motor coach and the trailer could be buffer locking because of the radius of the curve; the buffers of one vehicle are in too tight a contact with the buffers of the other, and hence the lighter one will come off the track.
Try looking at that for a first shot.
HTH
Martyn
Or maybe one of the couplings isn't able to move in it's pocket for some reason.
Try very gently easing the coupling left and right to see if something is causing it to stick .