1520 mm Gauge Railways Geography
1520 mm (1524 mm (5 ft)) gauge is known in the English-speaking world as "Russian gauge"e; so we'll use this term here too.
The primary installed base of Russian gauge is across the states of the former Soviet Union (CIS states, Baltic states and Georgia), also Mongolia and Finland, representing ca. 225,000 km (140,000 mi) of track. The Russian gauge is the second most widely used gauge in the world—after 1,435 mm (4 ft 8 1⁄2 in) (standard gauge).
Countries currently using the Russian gauge (as a main railway gauge in a country)Armenia
Comparatively short sections of Russian-gauge railways also extend beyond the borders of the former USSR, Mongolia and Finland into Poland, eastern Slovakia, Sweden (at the Finnish border at Haparanda), and northern Afghanistan.
Besides 1520 mm gauge is also used at Sassnitz/Mukran ferry terminal (Germany) for freight train ferries to Turku, Klaipėda and Baltijsk, at Varna ferry terminal (Bulgaria) for train ferries to Odessa and Poti;
Hong Kong Peak Tram also uses 1520 mm gauge.
Until 2000 Panama Canal Railway also used 1524 mm gauge.
In the South of the USA (except Florida) before the Civil War 1524 mm was widely used.