Checked with meter, the power pack is putting out AC.

I did find a manual for the auto reverse set online that has a photo of the speed controller, and the jack is supposed to be marked 'To reversing track' whilst mine says simply 'to track'.

I bought the set used and seems I got a bad speed controller as well as being the wrong one.

Checked, then tried with just the two end pieces with split rail, and indeed also with just the terminal track. Car just lights up and buzzes, loudly, and with no change in volume relative to the 'speed' setting. Tried reverse switch, tried reversing car orientation, and car works on other layout.

I purchased a used Bachmann auto reverse trolley set, the bundle that had the trolley and building. When assembled with the cut rail sections at the ends the trolley ( and another loco I tried)  just lights up and vibrates. I put the trolley on my regular layout and it works fine.

Since it appears upon looking  that the trolley has no special electronics, and the underside of the track has multiple taps but no obvious electronics, I assume the reverse function is in the grey controller which connects to the track via a 3.5mm four conductor jack.

Do I have the wrong controller? It appears like the one on the package, but the part number 46605A when googled just comes up as a normal power controller with no mention of a auto reverse function.

Thanks for any help!
 Mark

P.S. Tried to reply but was denied, so, also tried to upload a photo the underside of the tracks but it says the upload folder is full? 

The two tracks only have wires underneath, there are no components. SO while the end tracks have a split rail, and wiring to each I don't see any components capable of causing the reverse operation. Even with only the piece of track from the shed connected, the trolley or any loco just lights up and buzzes. But works fine on my regular layout.