4th rail but no 3rd rail can lead to unexpected effects, especially if there are no 4th rail trains.

If you want to use the Metro track set alongside this NewGRF (admittedly redundant), enable the compatibility trick on this NewGRF. That setting should not be needed in other situations, but it's there just in case.

You need to make this load after PURR (so this needs to be lower in the list) or some things won't work.

Thanks to NuTracks for the graphics and for some code!