Metre gauge is the system of narrow gauge railways and tramways with a track gauge of . It has installations of around in the world. It is the main gauge in some countries. In Europe large metre gauge networks remain in continuous use in Switzerland, northern Spain and for many European urban trams, although most metre gauge local railways in France, Germany, and Belgium closed down in the mid 20th century. With the revival of urban rail transport, in some cities metre gauge light metros were established, while in other cities metre gauge was replaced by standard gauge.