Service alert for Lionel subway trains. If you were running the full six car set, these trains are quite heavy. If you notice when the subway starts to takeoff it shutters a second, this is a sign. One of the motors is starting to fail. The easiest way to check is the place the power unit on its side and hook up power to it then as you slowly accelerate watch the trucks the truck that hesitates is the one with the motor that is going bad. Just had one go bad and I am now waiting on a motor replacement from Lionel. While you have these cars open put a TVS in to protect the electronics. You will have to put a TVS in every subway car as they all draw power from the mainline and have an electronic board in each car.
Original Post
