Jim,
Here are two photos of what the unit should look like.
Unfortunately, your motor, which look like this
Is missing the outer casing and the reverse bar.
The bar is designed to catch a track mounted trip on the side of the track and move to the opposite direction, triggering the reverse mechanism. What it basically does is move the outer bars away from the center connection, which provides power. So whichever bar touches the center bar, has power and feeds to one side of the armature.
Nobody reproduces these parts, so you either have to find a junker or remove the reverse unit entirely.
I believe that each wire at the top goes to either side of the armature, but I would have to double check.
