Jerry,
You need to be able to look at Greenburg's Repair and Operating Manuel for Lionel Trains, page 440 of the seventh edition, for Postwar trains. It shows the wiring diagram for the Transfer Table controller and how it connects/operates with the table itself. All three rails on the Trans Table rail bed assembly are powered from the transformer power (hot) post. It is the momentary contact with power to the rails that determines the direction of travel for the table, and when the table engine track is powered to allow movement of the engines being transferred. This could be accomplished with use of momentary push buttons, or with spring loaded toggle switches. You should be able to find what direction of travel the table moves by touching a "hot" wire to either of the outside rails, ground or "U" attached to rail bed frame. Use caution and DO NOT apply power to BOTH outside rails at the same time, it will quite possibly burn out your motor in the table "house". The center rail is the "hot" side of the table track to power up any motive power sitting on the table and being transferred.
Hope this helps.
Jesse TCA