Why not use the old magnets under the road trick? I've seen this done to excellent effect.
I was kidding about the Nurburgring in response to John's comment about horse drawn wagons on my layout.
The way to go car racing is on computer simulators like xbox. But slot cars is another hobby that is seeing a renaissance thanks in part to digital technology. Rob Schleicher, who started a slot car magazine in addition to RMJ, once stopped by my house a few years ago and tried to talk me into building a slot car track where I now have my expanded harbor scene. His RMC magazine has disappeared, but his slot car magazine is still going.
Now, animating a horse drawn wagon would be a task. I suppose if the horse were just slowly walking it might be possible to articulate the legs in a crude manner. Add that to my layout do list.
