The only mod-content used is nixie-tubes, for a convenient display. Any other method could be used instead. The big display counts off a lap counter, which I have primarily used for fuel-economy tests. The small counters are lap counters.
Theory of operation There are a few moving parts to this, although the overall concept is pretty simple. The track is a 100-tile (50-rail-piece) loop with a counter and timers.If anyone wants to use this sort of scheme to do some of their own benchmarking, here's a blueprint string for it.