When Hornby Dublo introduced their 00 scale three rail system, one of the features exploited on their recommended layouts was the simple ability to reverse the direction of a train without the involvement of electrical switching, only track. Remember with this system, forward is always forward on the line controller. If you pick up and turn around a locomotive and then reapply power in the same direction, the locomotive will run in the opposite direction to before, in fact just as DCC systems do now.
It is quite possible to have reversing loops on two rail layouts, but it does require the use of correctly located single rail gaps and a bit of wiring. The first one requires one point, dead or alive and a turn back loop. Attached to the point a single changeover accessory switch requires to be fitted. Trains may be run around the loop in either direction depending on the setting of the point but must be stopped in the turn back loop for the point to be changed and the direction switch on the line controller to be reversed. Gaps should be located as shown and the three wires installed as on the diagram.
There you are, three ways to turn back.