Is it possible that the LGB sliders are touching the "opposite rail" through the turn-out causing a short circuit?
This is actually a fairly common occurance with some makes and I have personally seen this happen. Try putting a piece of tape over that area where this could occur so there is no possiblility of it occuring and try again. If it still stops, I would agree that is is a loss of power rather than a momentary short circuit.
This is actually a fairly common occurance with some makes and I have personally seen this happen. Try putting a piece of tape over that area where this could occur so there is no possiblility of it occuring and try again. If it still stops, I would agree that is is a loss of power rather than a momentary short circuit.