David and Ed - Thank you both for the information.
For indoor use:
I had thought about adapting a 'toy' I had as a child. - Matchbox Motorway.
This had track (road) sections a little like those for top racing cars, but you had a long-length of spiral spring, which you fed into the groove in the roadway, once laid.
A hut had a motor and gears, which a large final gear-wheel drove the spring round the roadway.
They supplied plastic pegs, with a flat 'plate' at one end, and some silver-foil stickers with a hole in. - You used these to mount the pin on the bottom of any Matchbox vehicle. The pin dropped into the slot, and the moving spring dragged the car(s) round the roadway.
You could put several cars on at the same time. Hence 'Motorway' rather than 'Racetrack', I suppose?
It was a little noisy, as there was a 'whooshing sound' from the spring travelling round in the track.
If you did use it for racing.. A car with a towing-hitch, would allow a fine piece of wire to be added at the rear.. Your car would then not spin off the track at speed!