After a bit of googling, I came across a product called Scalextric Challenger. This seems to have been sold for a couple of years around 2004. Web reviews were varied but if it worked, it was what I was after. These occasionally come up on eBay second-hand but seem to be quite costly and hard to get hold of. Amazingly, I managed to find one brand new in stock in a railway model shop on the South Coast. I snapped it up.
From the box cover:
Pit yourself against the intelligent race system. Challenger learns any circuit then races it to the maximum. New Mercedes CLK with on-board computer intelligence. High tech trackside control gantry with LED countdown.Inside the box you get the car (I have the alternative black version), a strip with a pair of magnets, a set of controller keys, and the control gantry and base.
Out of the box, here's the bits needed with the gantry put together. The magnets go under the track so that the car can detect where the start-finish line is (I just used a flat magnet as this one clips on the side of the track, which can't be done with borders fitted). The control gantry takes a couple of AA batteries and is effectively a remote starter for the car - IR transmitter at top, with red and green lights for countdown underneath. On the back are three buttons to instruct the car: Learn, and two race modes Slow and Fast. The controller keys are for different manufacturers systems and replace the usual controller so that full power is sent to the track at all times.
To use it, you place the car on the track near the start-finish line and it will slowly creep forward until it detects the magnet. Then press the Learn button and the car does two slow laps, its on-board processor memorizing the track by recording the position of the guide as it goes round. After two laps, the car will stop again at the start line, you press a Race button and it goes off at speed when the lights turn green.
So does it work?
No, not out of the box. I found the car much too fast even in Learn mode. It would deslot on my hairpins and after helping it round those so it could actually learn the track, as soon as it was at race speed it would come off on many of the corners. Very frustrating.
Some websites suggested truing the tyres or swapping them for slicker ones. That didn't help. But some suggested an extra magnet to keep the back end from swinging out on the corners quite so much. That worked! With the addition of a bar magnet behind the rear axle (initially blu-tacked, but to be epoxied next) the car stays on the track all the way round, and proves to be a challenging competitor.
Here's a short video of the car learning and then racing my home track.
It's also an unforgiving competitor. Of course it doesn't stop until the end of the race, so it won't slow down to let me catchup after I de-slot and, much worse, it won't stop if I've come off into its lane - it will just pile on into me! So I may wire in a momentary push button at the controller key which will act to switch the car back into creep mode.
Of course I'd rather be racing against a real person but this is an effective extra challenge when I'm using the track on my own.
