There might be another problem here. I just realized that this engine doesn't have rollers. It has sliding shoes which have a tendency to be a real PITA. If not adjusted properly, they lose contact with the center rail and that will make the engine stall or......switch gears. This is especially true over switches or on curves. Bend them down to create more pressure and contact on the rail, but it's performance will never be the same as an engine with rollers.
Roger
