Don,
I gave that a try, just out of curiosity, before I took the Streets track down. The magnet on the car just adheres itself to the outside rail, and if you try to use the thinner center rail then the wheels also end-up in the ruts. It might work if you created some separation between the rail and the magnet... but I imagine that would start to stray into Rube Goldberg territory
-Dustin