A train with 258 would appear to be a train with 258 mod 256 = 2 axles. The purpose of the counters isn't really to count how big the trains are, just to keep

A train with 258 would appear to be a train with 258 mod 256 = 2 axles. The purpose of the counters isn't really to count how big the trains are, just to keep track of them. So it at least knows there is a train on the tracks.