I have had quite a bit of trouble with the MTH electro box coupler. Most all the problem ones have the coupler pointing off center. Not aligned correctly at the factory. It is especially troublesome when two cars are together with the same issue. Look at each one as it sits on the track, making sure the uncoupling tab is not binding on the plunger (another annoying issue). If the truck is on the track straight, the coupler should line up nicely with the center rail. If it points to one side or the other, it may be causing a problem, especially on tighter diameter track. As mentioned earlier, not enough slack in the pick up wire can be an issue also.
Steve
