The following is a list of tram/streetcar (including heritage trams/heritage streetcars), or light rail systems with their track length, track gauge, electrification system. The vast majority of tram systems use 1,435 mm (4 ft 8+1⁄2 in) standard gauge. Generally, standard gauge is the standard for every brand new system (except for the former Soviet Union), even in places where there is another gauge for the heavy rail. Metre gauge is mainly present in some old, continuously operating systems in Central Europe. Russian gauge is used only in the former Soviet Union. While in Central Europe the standard gauge and metre gauge coexist, in the former Soviet Union only the Russian gauge is used.