Is it the track that makes the trolley reverse, or is it an add on in the trolley unit.
I already own a few trolly units.
Thanks
The Bachmann auto-reversing trolley has all of the reversing circuitry in the "barn" that comes with the set. The reversing track just allows the circuitry to continue.
If you're just looking to use auto-reversing for your existing trolley's, your best bet would be to get something from another manufacturer. To use the Bachmann equipment, then you'll have to purchase the whole set. I believe that there are several manufacturers that sell reversing units. Some that you can even set up stops with delays.
Kevin
BJW,
I was checking through the Walther's on-line catalog for some other items and found an Automatic Reversing Unit #564-525. It is described as "automatically reverses train direction without the need for track switches, optical sensors, special lights or other devices". It can be used for automatic single or multitrac point-to point operation. The product is on sale today for $59.98. I don't know if this will meet your needs, but check their catalog for a picture. It's made by Peerless Industries and operates on any 12V DC power supply.
Bill