Question: What is the usage for the track gauge that is the second-widest gauge in regular use ?

text: Track gauge
Dominant gauges
Approximately 55% of the world 's railways use the 1,435 mm ( 4 ft 8 1⁄2 in ) standard gauge [ citation needed ] . Further information : List of track gauges
In rail transport, track gauge or track gage is the spacing of the rails on a railway track and is measured between the inner faces of the load-bearing rails. All vehicles on a rail network must have running gear that is compatible with the track gauge, and in the earliest days of railways the selection of a proposed railway's gauge was a key issue. As the dominant parameter determining interoperability, it is still frequently used as a descriptor of a route or network. In some places there is a distinction between the nominal gauge and the actual gauge, due to divergence of track components from the nominal. Railway engineers use a device, like a caliper, to measure the actual gauge, and this device is also referred to as a track gauge. The terms structure gauge and loading gauge, both widely used, have little connection with track gauge. Both refer to two-dimensional cross-section profiles, surrounding the track and vehicles running on it. The structure gauge specifies the outline into which new or altered structures (bridges, lineside equipment etc.) must not encroach. The loading gauge is the corresponding envelope within which rail vehicles and their loads must be contained. If an exceptional load or a new type of vehicle is being assessed to run, it is required to conform to the route's loading gauge. Conformance ensures that traffic will not collide with lineside structures.
Gauge Name Installation ( km ) Installation ( miles ) Usage
1,000 mm ( 3 ft 3 ⁄ 8 in ) Metre gauge 95,000 59,000 Argentina ( 11,000 km or 6,800 mi ) , Brazil ( 23,489 km or 14,595 mi ) , Bolivia , northern Chile , Spain ( Feve , FGC , Euskotren , FGV , SFM ) , Switzerland ( RhB , MOB , BOB , MGB ) , Malaysia , Thailand , Indochina , Bangladesh , East Africa ( approx . 7% of the world 's railways )
1,067 mm ( 3 ft 6 in ) Three foot six inch gauge 112,000 70,000 Southern and Central Africa , Nigeria ( most ) , Indonesia , Japan , Taiwan , Philippines , New Zealand , Queensland , Australia , Western Australia and South Australia . ( approx . 9% of the world 's railways )
1,435 mm ( 4 ft 8 ⁄ 2 in ) Standard gauge 720,000 450,000 Albania , Argentina , Australia , Austria , Belgium , Bosnia and Herzegovina , Brazil ( 194 km or 121 mi ) , Bulgaria , Canada , China , Croatia , Cuba , Czech Republic , Denmark , Djibouti , DR Congo ( Kamina-Lubumbashi section , planned ) , Ethiopia , France , Germany , Great Britain ( United Kingdom ) , Greece , Hungary , India ( only used in rapid transit ) , Indonesia ( Aceh and Sulawesi ) , Italy , Israel , Liechtenstein , Lithuania ( Rail Baltica ) , Luxembourg , Macedonia , Mexico , Montenegro , Netherlands , North Korea , Norway , Panama , Peru , Philippines , Poland , Romania , Serbia , Slovakia , Slovenia , South Korea , Spain ( AVE , Alvia and FGC ) , Sweden , Switzerland , Turkey , United States , Uruguay , Venezuela , Also private companies ' lines and JR high-speed lines in Japan . High-speed lines in Taiwan . Gautrain commuter system in South Africa . ( approx . 55% of the world 's railways )
1,520 mm ( 4 ft 11 ⁄ 32 in ) Five foot and 1520 mm gauge 220,000 140,000 Armenia , Azerbaijan , Belarus , Finland , Estonia , Georgia , Kazakhstan , Kyrgyzstan , Latvia , Lithuania , Moldova , Mongolia , Russia , Tajikistan , Turkmenistan , Ukraine , Uzbekistan . ( approx . 17.2% of the world 's railways ; all contiguous - redefined from 1,524 mm ( 5 ft ) )
1,524 mm ( 5 ft ) Finnish gauge 5,865 3,644 Finland ( contiguous to and generally compatible with 1,520 mm ( 4 ft 11 ⁄ 32 in ) )
1,600 mm ( 5 ft 3 in ) Five foot three inch gauge 9,800 6,100 Ireland , Northern Ireland ( United Kingdom ) ( 1,800 km or 1,100 mi ) , and in the Australian states of Victoria and South Australia ( 4,017 km or 2,496 mi ) , Brazil ( 4,057 km or 2,521 mi )
1,668 mm ( 5 ft 5 ⁄ 32 in ) Iberian gauge 15,394 9,565 Portugal , Spain . Sometimes referred to as Iberian gauge . In Spain the Administrador de Infraestructuras Ferroviarias ( ADIF ) managed 11,683 km ( 7,259 mi ) of this gauge and 22 km ( 14 mi ) of mixed gauge at end of 2010 . The Portuguese Rede Ferroviária Nacional ( REFER ) managed 2,650 km ( 1,650 mi ) of this gauge of this track at the same date
1,676 mm ( 5 ft 6 in ) Five foot six inch gauge 134,008 83,269 India , Pakistan , Bangladesh , Sri Lanka , Argentina , Chile , BART in the United States San Francisco Bay Area ( approx . 11.37% of the world 's railways )