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A standard-gauge railway is a railway with a track gauge of (). The standard gauge is also called Stephenson gauge (after George Stephenson), International gauge, UIC gauge, uniform gauge, normal gauge and European gauge in Europe. It is the most widely used railway track gauge across the world, with approximately 55% of the lines in the world using it. All high-speed rail lines use standard gauge except those in Russia, Finland, Portugal and Uzbekistan. The distance between the inside edges of the rails is defined to be 1435 mm except in the United States and on some heritage British lines, where it is defined in U.S. customary/Imperial units as exactly "four feet eight and one half inches" which is equivalent to 1435.1mm.
As railways developed and expanded, one of the key issues was the track gauge (the distance, or width, between the inner sides of the rails) to be used. Different railways used different gauges, and where rails of different gauge met - a "gauge break" - loads had to be unloaded from one set of rail cars and re-loaded onto another, a time-consuming and expensive process. The result was the adoption throughout a large part of the world of a "standard gauge" of (), allowing interconnectivity and interoperability.
A popular legend that has been around since at least 1937 traces the origin of the () gauge even further back than the coalfields of northern England, pointing to the evidence of rutted roads marked by chariot wheels dating from the Roman Empire.[a] Snopes categorised this legend as "false", but commented that "it is perhaps more fairly labelled as 'True, but for trivial and unremarkable reasons'". The historical tendency to place the wheels of horse-drawn vehicles approximately apart probably derives from the width needed to fit a carthorse in between the shafts. Research however has been undertaken which supports the hypothesis that "the origin of the standard gauge of the railway might result from an interval of wheel ruts of prehistoric ancient carriages".
In addition, while road-travelling vehicles are typically measured from the outermost portions of the wheel rims (and there is some evidence that the first railways were measured in this way as well), it became apparent that for vehicles travelling on rails it was better to have main wheel flanges that fit inside the rails, and thus the minimum distance between the wheels (and, by extension, the inside faces of the rail heads) was the important one.
There was never a standard gauge for horse railways but there were rough groupings: in the north of England none was less than . Wylam colliery's system, built before 1763, was , as was John Blenkinsop's Middleton Railway; the old plateway was relaid to so that Blenkinsop's engine could be used. Others were (in Beamish) or (in Bigges Main (in Wallsend), Kenton, and Coxlodge).
The English railway pioneer George Stephenson spent much of his early engineering career working for the coal mines of County Durham. He favoured for wagonways in Northumberland and Durham, and used it on his Killingworth line. The Hetton and Springwell wagonways also used this gauge.
Stephenson's Stockton and Darlington railway (S&DR) was built primarily to transport coal from mines near Shildon to the port at Stockton-on-Tees. The initial gauge of was set to accommodate the existing gauge of hundreds of horse-drawn chaldron wagons that were already in use on the wagonways in the mines. The railway used this gauge for 15 years before a change was made to the () in gauge. The historic Mount Washington Cog Railway, the world's first mountain-climbing rack railway, is still in operation in the 21st century, and has used the earlier gauge since its inauguration in 1868.
George Stephenson used the () gauge (including a belated extra 1⁄2 in (13 mm) of free movement to reduce binding on curves) for the Liverpool and Manchester Railway, authorised in 1826 and opened 30 September 1830. The success of this project led to Stephenson and his son Robert being employed to engineer several other larger railway projects. Thus the gauge became widespread and dominant in Britain. Robert was reported to have said that if he had had a second chance to choose a standard gauge, he would have chosen one wider than . "I would take a few inches more, but a very few".
During the "gauge war" with the Great Western Railway, standard gauge was called narrow gauge, in contrast to the Great Western's broad gauge. The modern use of the term "narrow gauge" for gauges less than standard did not arise for many years, until the first such locomotive-hauled passenger railway, the Ffestiniog Railway was built.
In 1845, in the United Kingdom of Great Britain and Ireland, a Royal Commission on Railway Gauges reported in favour of a standard gauge. The subsequent Gauge Act ruled that new passenger-carrying railways in Great Britain should be built to a standard gauge of , and those in Ireland to a new standard gauge of . In Great Britain, Stephenson's gauge was chosen on the grounds that existing lines of this gauge were eight times longer than those of the rival or (later or ) gauge adopted principally by the Great Western Railway. It allowed the broad-gauge companies in Great Britain to continue with their tracks and expand their networks within the "Limits of Deviation" and the exceptions defined in the Act. After an intervening period of mixed-gauge operation (tracks were laid with three rails), the Great Western Railway finally completed the conversion of its network to standard gauge in 1892. In North East England, some early lines in colliery (coal mining) areas were , while in Scotland some early lines were . All these lines had been widened to standard gauge by 1846. The British gauges converged starting from 1846 as the advantages of equipment interchange became increasingly apparent. By the 1890s, the entire network was converted to standard gauge.
The Royal Commission made no comment about small lines narrower than standard gauge (to be called "narrow gauge"), such as the Ffestiniog Railway. Thus it permitted a future multiplicity of narrow gauges in the UK. It also made no comments about future gauges in British colonies, which allowed various gauges to be adopted across the colonies.
Parts of the United States, mainly in the Northeast, adopted the same gauge, because some early trains were purchased from Britain. The American gauges converged, as the advantages of equipment interchange became increasingly apparent. Notably, all the broad gauge track in the South was converted to "almost standard" gauge over the course of two days beginning on 31 May 1886. See Track gauge in the United States.
In continental Europe, France and Belgium adopted a () gauge (measured between the midpoints of each rail's profile) for their early railways. The gauge between the interior edges of the rails (the measurement adopted from 1844) differed slightly between countries, and even between networks within a country (for example, or to or in France). The first tracks in Austria and in the Netherlands had other gauges ( or in Austria for the Donau Moldau linen and or in the Netherlands for the Hollandsche IJzeren Spoorweg-Maatschappij), but for interoperability reasons (the first rail service between Paris and Berlin began in 1849, first Chaix timetable) Germany adopted standard gauges, as did most other European countries.
The modern method of measuring rail gauge was agreed in the first Berne rail convention of 1886, according to the "Revue générale des chemins de fer, July 1928".
|Albania||National rail network||339 km (211 mi)|
|Algeria||3,973 km (2,469 mi)|
|Angola||80 km (50 mi)|
|Argentina||Other major lines are mostly broad gauge, with the exception of the () General Belgrano Railway.|
Victoria built the first railways to the Irish broad gauge. New South Wales then built to the standard gauge, so trains had to stop on the border and passengers transferred, which was only rectified in the 1960s. Queensland still runs on a narrow gauge but there is a standard gauge line from NSW to Brisbane.
|Austria||Österreichische Bundesbahnen||4,859 km (3,019 mi) The Semmering railway has UNESCO World Heritage Site status.|
|Bangladesh||To be used only for rapid transit system, Dhaka Metro Rail||20.1 km (12.5 mi)|
|Belgium||NMBS/SNCB, Brussels Metro and tramway||339 km (211 mi)|
|Bosnia and Herzegovina||
1,032 km (641 mi)
|Brazil||Estrada de Ferro do Amapá; from Uruguaiana to the border with Argentina and from Santana do Livramento to the border with Uruguay (both mixed gauge and or ); remaining tracks at Jaguarão, Rio Grande do Sul (currently inoperable); Rio de Janeiro Light Rail; São Paulo Metro lines 4 and 5; Salvador Metro Baixada Santista Light Rail||205.5 km (127.7 mi)|
|Canada||National rail network (including commuter rail operators like GO Transit, West Coast Express, AMT and Union Pearson Express).||49,422 km (30,709 mi)
The Toronto Transit Commission uses gauge on its streetcar and subway lines.
|China||National rail network||103,144 km (64,091 mi)|
|Chile||Santiago Metro||140.800 km (87 mi)|
|Colombia||Metro de Medellín, Tren del Cerrejón, Metro de Bogotá|
|Cuba||Ferrocarriles de Cuba||4,266 km (2,651 mi)|
|Czech Republic||9,478 km (5,889 mi)|
|Denmark||Banedanmark and Copenhagen Metro|
|Djibouti||Addis Ababa-Djibouti Railway||100 km (62 mi)|
|Egypt||Egyptian National Railways|
|Estonia||Rail Baltica||Standard-gauge Rail Baltica railway is under construction and is scheduled to be completed by 2026.|
|Ethiopia||Addis Ababa-Djibouti Railway; Addis Ababa Light Rail||659 km (409 mi) Other standard gauge lines under construction.|
|France||SNCF, RATP (on RER lines)|
|Gabon||Trans-Gabon Railway||669 km|
|Germany||Deutsche Bahn, numerous local public transport providers||43,468 km (27,010 mi)|
|Georgia||Georgian Railway () constructed between Akhalkalaki to Karstakhi for Baku-Tbilisi-Kars Railway||26.142 km (16.244 mi)|
|Greece||Hellenic Railways Organisation (operated by TrainOSE)||All modern Greek networks, except in the Peloponnese|
|Holy See||1 km (0.62 mi)|
|Hong Kong||MTR (former KCR network - East Rail line, West Rail line, Tuen Ma line, Light Rail)||Other MTR lines use 1,432 mm (4 ft 8+3⁄8 in) instead of 4 ft 8+1⁄2 in|
|India||Only used for rapid transit and tram, Bangalore Metro, Chennai Metro, Delhi Metro (Phase 2 onwards), Rapid Metro Gurgaon, Hyderabad Metro, Jaipur Metro, Kochi Metro, Kolkata Metro (Line 2 onwards), Lucknow Metro, Mumbai Metro, Nagpur Metro, Navi Mumbai Metro and Trams in Kolkata. The under construction Mumbai-Ahmedabad high-speed rail corridor based on the Shinkansen also uses standard gauge. All of the under-construction and future rapid transit systems would be in standard gauge.||Indian nationwide rail system (Indian Railways) uses broad gauge.|
|Indonesia||The very first railway line in Indonesia which connects Semarang to Tanggung, which later extended to Yogyakarta was laid to standard gauge. Opened in 1867, it was mostly regauged to 1,067mm/3ft6in during Japanese occupation in 1943, while a short line in Semarang Harbor soldiered on until 1945.
Standard gauge railway lines made a return in 2014 on experimental railway line in Aceh. The first large scale standard gauge network made returns in 2019 in form of Jakarta LRT network, and in the near future the Jakarta MRT Phase 3 and Jakarta-Bandung high speed network will be laid to standard gauge as well.
|Rest of the country uses in Java and Sumatra .|
|Iran||Islamic Republic of Iran Railways||12,998 km (8,077 mi)|
|Iraq||Iraqi Republic Railways||485 km (301 mi)|
|Ireland||Transport Infrastructure Ireland||Luas in Dublin|
|Israel||Israel Railways, CTS, operating the Jerusalem Light Rail|
|Italy||Ferrovie dello Stato||16,723 km (10,391 mi)|
|Japan||Shinkansen, JR Hokkaido Naebo Works (see Train on Train), Keisei Line, Keikyu Line, Tokyo Metro (Ginza and Marunouchi lines), Toei Subway (Asakusa and Oedo lines), Kintetsu Railway (Osaka, Nara, Nagoya, Yamada, Kyoto, and Keihanna lines and their associated branches), Keihan Railway, Hankyu Railway, Hanshin Railway, Kyoto Municipal Subway, Kobe Municipal Subway, Osaka Metro, Kita-Osaka Kyuko Railway, Fukuoka City Subway (Nanakuma Line), Sendai Subway (Tozai Line), Nagoya Municipal Subway (Higashiyama, Meij?, and Meik? lines), Nose Electric Railway, Yokohama Municipal Subway (Blue and Green lines)||4,251 km (2,641 mi), all electrified|
|Kenya||Mombasa-Nairobi Standard Gauge Railway||485 km (301 mi) Inaugurated 31 May 2017. An extension from Nairobi to Naivasha is under construction. A further extension east to the Ugandan border is planned.|
|Latvia||Rail Baltica||Standard-gauge Rail Baltica railway is under construction and is scheduled to be completed by 2026.|
|Lebanon||All lines out of service and essentially dismantled|
|Libya||Network under construction|
|Lithuania||Rail Baltica||First phase, from Kaunas to the Polish border, completed in 2015. Second phase, from Kaunas north to Tallinn and from Kaunas to Vilnius, is in the design and construction phase and scheduled to be completed by 2026.|
|Luxembourg||Société Nationale des Chemins de Fer Luxembourgeois|
|Malaysia||998 km (620 mi)|
|Mexico||24,740 km (15,370 mi)|
|Montenegro||?eljeznice Crne Gore||3|
|Morocco||Rail transport in Morocco||2,067 km (1,284 mi)|
|Netherlands||Nederlandse Spoorwegen and regional railways.|
|New Zealand||Rail_transport_in_New_Zealand||3'6" Narrow gauge chosen due to the need to cross mountainous terrain in the country's interior and the lower cost of construction|
|Nigeria||Lagos-Kano Standard Gauge Railway; Lagos Rail Mass Transit||Under construction; Abuja to Kaduna section operational.|
|North Korea||Railways of the DPRK.|
|North Macedonia||Macedonian Railways|
|Norway||Norwegian National Rail Administration, Rail transport in Norway||4,087 km (2,540 mi)|
|Pakistan||To be used only for rapid transit system, Lahore Metro||Pakistan's nationwide rail system (Pakistan Railways) uses broad gauge. Any future additions to this system would also be in broad gauge.|
|Panama||Panama Railway; Panama Metro||Regauged from in 2001|
|Paraguay||Ferrocarril Presidente Don Carlos Antonio López, now Ferrocarril de Paraguay S.A. (FEPASA)||36 km out of Asunción (used as a tourist steam line), plus 5 km from Encarnación to the border with Argentina, carrying mainly exported soy; the rest of the 441-km line awaits its fate, while redevelopment plans come and go with regularity. The section from west of Encarnación to north of San Salvador, plus the entire San Salvador-Abaí branch, have been dismantled by the railway itself and sold for scrap to raise funds.|
|Peru||Railway Development Corporation, Ferrocarril Central Andino (Callao-Lima-La Oroya-Huancayo and La Oroya-Cerro del Pasco lines), Ferrocarril del sur de Peru (operated by Peru Rail) Matarani-Arequipa-Puno and Puno-Cuzco, Ilo-Moquegua mining railway, Tacna-Arica (Chile) international line, (operated by Tacna Province), Lima electric suburban railway||1,603 km (996 mi)|
|Philippines||Manila LRT and MRT (present)||50.3 km (31.3 mi) line length, all electrified as of 2010.|
|Philippine National Railways network, future LRT and MRT Lines (proposed)||c. 4,600 km (2,900 mi), 1,159 km (720 mi) will be electrified.[b]|
|Poland||Polskie Koleje Pa?stwowe, Warsaw Metro, most tramway systems throughout the country|
|Portugal||Planned high-speed lines, Braga and Oporto (Guindais) funiculars, Lisbon Metro, Oporto Metro (partly adapted from former () ; tracks), Metro Transportes do Sul light rail in Almada.||All other railways use () (broad gauge); some use () ; Decauville uses () gauge.|
|Russia||Rostov-on-Don tramway, lines connecting Kaliningrad with Poland|
|Rwanda||Isaka-Kigali Standard Gauge Railway||150 km (93 mi) New railway between Kigali and the Tanzanian town of Isaka is planned.|
|Saudi Arabia||Rail transport in Saudi Arabia|
|Singapore||Mass Rapid Transit||203 km (126 mi)|
|Slovakia||?eleznice Slovenskej republiky, Ko?ice tramway system|
|South Africa||Gautrain in Gauteng Province. Rest of country uses||80 km (50 mi)|
|Spain||AVE high-speed rail lines from Madrid to Seville, Málaga, Saragossa, Barcelona (-Perthus), Toledo, Huesca, and Valladolid, Barcelona Metro (L2, L3, L4, and L5 lines), Barcelona FGC (lines L6 and L7), and Metro Vallès (lines S1, S2, S5, and S55)
All other railways use () (broad gauge) and/or () .
|2,571 km (1,598 mi)|
|Sweden||Swedish Transport Administration, Storstockholms Lokaltrafik (Stockholm metro, commuter and light rail lines), tram networks in Gothenburg and Norrköping|
|Switzerland||Swiss Federal Railways,||SFR 3,134 km in standard gauge and 98 km metre gauge
449 km[clarification needed]
|Syria||Chemins de Fer Syriens||2,052 km (1,275 mi)|
|Taiwan||604.64 km (376 mi)|
|Tanzania||Tanzania Standard Gauge Railway||202 km (126 mi) line from Dar es Salaam to Morogoro under construction. Contract awarded in 2019 for a 422 km (262 mi) extension from Morogoro to Makutupora.|
|Thailand||80 km (50 mi)|
|Tunisia||Northern part of the network||471 km (293 mi)|
|Turkey||Turkish State Railways (also operates Marmaray), metro networks, and tram networks||Some tram networks use () .|
|Uganda||Uganda Standard Gauge Railway||Railway line from Kampala to the Kenyan border is planned.|
|United Arab Emirates||Rail transport in the United Arab Emirates|
|United Kingdom (Great Britain)||Entire rail network in Great Britain (but not Ireland) since standardisation by the Regulating the Gauge of Railways Act 1846||Also used on all metro and tramway systems with the exception of the self-contained Glasgow Subway, which is .|
|United States||129,774 km (80,638 mi)|
|Uruguay||National rail network||2,900 km (1,800 mi)|
|Vietnam||North of Hanoi||178 km (111 mi). Includes dual gauge (standard/metre) to the Chinese border.|