[woodcote]

Thanks Henk. Although I haven't translated it all, the info has appeared on various English-language slot car sites and forums in the past.

I have come across very similar wiring diagrams dating back 10-15 years - using routed track and 'old-fashioned' mechanical DPDT relays, solenoids etc. Model railroaders were certainly using this sort of set-up 40 years ago and probably slot car enthusiasts too. It has all been interesting and very useful to read, but I know from building other tracks that modern electronic components make the power control needed for projects like this much easier (and cheaper) - the model railways enthusiasts have moved on and so should we.

What the Scalextric pit lane exit and modern electronics offers is a more accessible plug & play version. Most of the circuitry in the diagram is replaced by a single board, not too difficult to put together from components or available ready-made for £4 here:  www.modellingelectronics.co.uk/products/reverse-polarity-switch-module/

When I receive and test the board I will post a picture on the thread - the wires I currently have soldered into a mechanical DPDT switch will simply screw into the terminal blocks on the board. I will add a push-to-make button attached to trigger the relay board - and then I can experiment with various lap sensing-type options to see which can most reliably replace the manual button to create an automatic system. Start simple, test, add complexity only if needed...

The other thing I did differently was to isolate the entire return loop and powered it from the driver station - that gives more time to successfully throw the polarity switch (manually or automatically). It also makes the circuitry simpler and acknowledges that slot cars run faster than trains.