[woodcote]

I have the reverse direction module working nicely with a push button - but only if I hold the button down as I go up the hill and let it go when I want to go back down...

Once the control voltage (Terminals 1 and 2) have power supplied to them the relay is activated and the output terminals of 5 and 6 will then change polarity.

Hmm, this info from the website could (and was) interpreted that applying momentary power to the relay flips the polarity / direction. In fact, a momentary burst of power only momentarily flips the polarity. The power has to stay on to maintain that change. What I need in between the dead strip (or any car-operated signal) and the reverse direction module is a latching relay. Thankfully, these are also available in similar ready-made modules. I have one on its way from a bloke in Wembley: fingers-crossed for Saturday.

In the meantime, I shall get everything tidied up...

   

Very pleasingly, I do have a working single-lane hillclimb / rally stage to have some fun with. The manually-operated reverse direction switch will do for now... it is a massive improvement over the mechanical switch. And when it arrives, I'll see if the latching relay is the final piece in the jigsaw for the automatic version. There might be more lessons to learn.