Instead of motorised cars taking power from a live track like Scalextric, this worked by a long continuous spring being driven round the track in a groove. By fixing a pin on the bottom of any matchbox car it would engage with the spring in the groove and be driven round the track. So any of your favourite Matchbox cars (or other make...although I seem to remember it struggling a bit with the larger scale Corgi or Dinky cars) could be raced.
You could either have two cars on seperate grooves going the same way, so that you could race them, or you could load it up with loads of cars and have the two tracks going in opposite directions like a motorway.
It even had a feature where BMW and Mercedes models driven by arrogant middles class tossers resentful that they couldn't afford a proper car like a Rolls or a Bentley could be driven within inches (to scale) of the more modest vehicle in front and ignore all the normal rules of the Highway Code. The Matchbox Range Rover with the Countryside Alliance sticker could be parked at the side of the track but unfortunately this meant that the rest of the cars stopped moving for some reason. An extension set was available with extra track and despite objections from my sister, planning permission for this extension was granted across the front room carpet and her toy conservation area had to be cut down.
Plans for a special Feltham edition where the cars could be stolen and driven off the motorway and set on fire by twelve year olds high on Booze and Drugs were abandoned for technical reasons.
Even poor condition examples of this toy are now going on eBay for as much as £3,500. Blimey!
Next week: the Action Man Deep Sea Diver.