The Imperial Russian narrow railway track gauge was 3 ft 6 in (1,067 mm), the current track gauge is predominantly 750 mm (2 ft 5+1⁄2 in). In Soviet Russia, narrow-gauge railways were mostly common in forestry and peat industries in low inhabited places. Usually they have one main line and number of temporary branches. There was commonly a passenger service to villages and towns for workers.
As of the mid 2010s, a number of industrial railways survive in places with bad roads, but every year some railways are closing.
A government railway operator, RZD, closed all owned common 750 mm railways, but still have a number of children's railways with standard rolling stock.
Sakhalin Railway. This railway was built by Japan who occupied southern Sakhalin after the Russo-Japanese War. The network was extended to the northern part of the island in the Soviet era. It was the last Russian railway in 3 ft 6 in (1,067 mm) and underwent conversion to 1,520 mm (4 ft 11+27⁄32 in) from 2003 to 2019.