# Standard-gauge railway

Track gauge :
By transport mode :
Rapid transit
Tram
Miniature
Scale model :
By size (list) :
Change of gauge :
Bogie exchange
Break of gauge
Dual gauge
Conversion
list
Variable gauge :
By location :
North America
South America
Europe
Australia :
A standard-gauge railway is a railway with a track gauge of 1,435 mm (4 ft 8+1⁄2 in). The standard gauge is also called Stephenson gauge (after George Stephenson), international gauge, UIC gauge, uniform gauge, normal gauge in Europe, and SGR in East Africa. It is the most widely used track gauge around the world, with about 55% of the lines in the world using it.
All high-speed rail lines use standard gauge except those in Russia, Finland, Uzbekistan, and some line sections in Spain. The distance between the inside edges of the heads of the rails is defined to be 1,435 mm except in the United States, Canada, and on some heritage British lines, where it is defined in U.S. customary/customary UK units as exactly "four feet eight and one half inches", which is equivalent to 1,435.1 mm.

## History

As railways developed and expanded, one of the key issues was the track gauge (the distance, or width, between the inner sides of the rail heads) to be used, as the wheels of the rolling stock (locomotives, cars, etc.) must match this distance. Different railways used different gauges, and where track of different gauges met – a "gauge break" – loads had to be unloaded from one set of rail cars and reloaded 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 1,435 mm (4 ft 8+1⁄2 in), allowing interconnectivity and interoperability.

### Origins

A popular legend that has circulated since at least 1937 traces the origin of the 1,435 mm (4 ft 8+1⁄2 in) 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. Snopes categorised this legend as "false", but commented that it "is perhaps more fairly labeled as 'Partly true, but for trivial and unremarkable reasons.'" The historical tendency to place the wheels of horse-drawn vehicles around 5 ft (1,524 mm) apart probably derives from the width needed to fit a carthorse in between the shafts. Research, however, has been undertaken to support 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, it became apparent that for vehicles travelling on rails, having main wheel flanges that fit inside the rails is better, thus the minimum distance between the wheels (and, by extension, the inside faces of the rail heads) was the important one.
A standard gauge for horse railways never existed, but rough groupings were used; in the north of England none was less than 4 ft (1,219 mm). Wylam colliery's system, built before 1763, was 5 ft (1,524 mm), as was John Blenkinsop's Middleton Railway; the old 4 ft (1,219 mm) plateway was relaid to 5 ft (1,524 mm) so that Blenkinsop's engine could be used. Others were 4 ft 4 in (1,321 mm) (in Beamish) or 4 ft 7+1⁄2 in (1,410 mm) (in Bigges Main (in Wallsend), Kenton, and Coxlodge).
English railway pioneer George Stephenson spent much of his early engineering career working for the coal mines of County Durham. He favoured 4 ft 8 in (1,422 mm) 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. Opening in 1825, the initial gauge of 4 ft 8 in (1,422 mm) 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, debuting around 1850, to the 1,435 mm (4 ft 8+1⁄2 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 4 ft 8 in (1,422 mm) gauge since its inauguration in 1868.
George Stephenson introduced the 1,435 mm (4 ft 8+1⁄2 in) 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 extra half inch was not regarded at first as very significant, and some early trains ran on both gauges daily without compromising safety.
The success of this project led to Stephenson and his son Robert being employed to engineer several other larger railway projects. Thus the 4 ft 8+1⁄2 in (1,435 mm) gauge became widespread and dominant in Britain. Robert was reported to have said that if he had had a second chance to choose a gauge, he would have chosen one wider than 4 ft 8+1⁄2 in (1,435 mm). "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 7 ft 1⁄4 in (2,140 mm) 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.

### Adoption

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 4 ft 8+1⁄2 in (1,435 mm), and those in Ireland to a new standard gauge of 5 ft 3 in (1,600 mm). 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 7 ft or 2,134 mm (later 7 ft 1⁄4 in or 2,140 mm) 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 4 ft 8 in (1,422 mm), while in Scotland some early lines were 4 ft 6 in (1,372 mm). 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 5 ft (1,524 mm) broad gauge track in the South was converted to "almost standard" gauge 4 ft 9 in (1,448 mm) 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 1,500 mm (4 ft 11+1⁄16 in) 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, 1,440 mm or 4 ft 8+11⁄16 in to 1,445 mm or 4 ft 8+7⁄8 in in France). The first tracks in Austria and in the Netherlands had other gauges (1,000 mm or 3 ft 3+3⁄8 in in Austria for the Donau Moldau line and 1,945 mm or 6 ft 4+9⁄16 in 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.

## Early railways by gauge
### Non-standard gauge

| Name | Authorised | Opened | Gauge |
| Monkland and Kirkintilloch Railway | 1824 | 1825 | 4 ft 6 in (1,372 mm) |
| Dundee and Newtyle Railway | 1829 | 1831 | 4 ft 6+1⁄2 in (1,384 mm) |
| Eastern Counties Railway | 1836, 4 July | 1839, 20 June | 5 ft (1,524 mm) |
| London and Blackwall Railway | 1838, 28 July | 1840 | 5 ft 1⁄2 in (1,537 mm) |
| Dundee and Arbroath Railway | 1836, 19 May incorporated | 1838, October | 5 ft 6 in (1,676 mm) Until standardised in 1847 |
| Arbroath and Forfar Railway | 1836, 19 May incorporated | 1838, November | 5 ft 6 in (1,676 mm) |
| Northern and Eastern Railway | 1836, 4 July | 1840, 15 September | 5 ft (1,524 mm) |
| Aberdeen Railway | 1845 | 1848 | 5 ft 6 in (1,676 mm) Until standardised |
| Great Western Railway | 1835 | 1838 | 7 ft 1⁄4 in (2,140 mm) Until standardised |
| Ulster Railway | 1836 | 1839 | 6 ft 2 in (1,880 mm) Until 5ft 3in |

### Almost standard gauge

* The Huddersfield Corporation Tramways, used 4 ft 7+3⁄4 in (1,416 mm)
* The Portsdown and Horndean Light Railway, used 4 ft 7+3⁄4 in (1,416 mm)
* The Portsmouth Corporation Transport, used 4 ft 7+3⁄4 in (1,416 mm)
* The Killingworth colliery railway, used 4 ft 8 in (1,422 mm).
* The Hetton colliery railway, opened 1822, used 4 ft 8 in (1,422 mm).
* The Stockton and Darlington Railway, authorised 1821, opened 1825, used 4 ft 8 in (1,422 mm).
* The New Orleans and Carrollton Railroad used 4 ft 8 in (1,422 mm)
* The Pontchartrain Railroad used 4 ft 8 in (1,422 mm)
* The trams in Nuremberg nominally used 1,432 mm (4 ft 8+3⁄8 in) during much of their existence, but have since been converted to standard gauge in name as well as fact.

### Standard gauge

| Name | Authorised | Opened | Remarks |
| Baltimore and Ohio Railroad | Begun 1827 | 1830 | |
| Liverpool and Manchester Railway | 1824 | 1830 | |
| Saint-Étienne–Lyon railway | 1826 | 1833 | All the early French railways (including Saint-Etienne Andrezieux, authorised 1823, opened 1827) had a French Gauge of 1,500 mm (4 ft 11+1⁄16 in) from rail axis to rail axis, compatible with early standard gauge tolerances) |
| Dublin and Kingstown Railway | 1831 | 1834 For passenger traffic | converted to 5 ft 3in |
| Newcastle & Carlisle Railway | 1829 | 1834 | Isolated from LMR |
| Grand Junction Railway | 1833 | 1837 | Connected to LMR |
| London and Birmingham Railway | 1833 | 1838 | Connected to LMR |
| Manchester and Birmingham Railway | 1837 | 1840 | Connected to LMR |
| Birmingham and Gloucester Railway | 1836 | 1840 | Connected to LMR |
| London and Southampton Railway | 1834 | 1840 | |
| London and Brighton Railway | 1837 | 1841 | |
| South Eastern Railway | 1836 | 1844 | |

### Small deviations from standard gauge

* The Manchester and Leeds Railway, authorised on 4 July 1836, used 4 ft 9 in (1,448 mm).
** The 4 ft 9 in (1,448 mm) railways were intended to take 4 ft 8+1⁄2 in (1,435 mm) gauge vehicles and allow a (second) running tolerance.
* The Chester and Birkenhead Railway, authorised on 12 July 1837, used 4 ft 9 in (1,448 mm).
* The London and Brighton Railway, authorised on 15 July 1837, used 4 ft 9 in (1,448 mm).
* The Manchester and Birmingham Railway, authorised on 30 June 1837, used 4 ft 9 in (1,448 mm).
* The Pennsylvania Railroad originally used 4 ft 9 in (1,448 mm)
* The trams in Dresden, authorised in 1872 as horsecars, used 1,440 mm (4 ft 8+11⁄16 in) gauge vehicles. Converted to 600 V DC electric trams in 1893, they now use 1,450 mm (4 ft 9+3⁄32 in); both gauges are within the tolerance for standard gauge.
* The Ohio gauge of 4 ft 10 in (1,473 mm)

### Dual gauge

* Cheltenham and Great Western Union Railway, authorised 1836, opened 1840, dual gauge 1843 4 ft 8+1⁄2 in (1,435 mm) standard gauge and 7 ft 1⁄4 in (2,140 mm).

### Initially standard gauge

Several lines were initially built as standard gauge but were later converted to another gauge for cost or for compatibility reasons.
* South Africa became 1,067 mm (3 ft 6 in)
* Thailand became 1,000 mm (3 ft 3+3⁄8 in)
* Indonesia became 1,067 mm (3 ft 6 in)
* Ireland became 1,600 mm (5 ft 3 in) – Dublin and Kingstown Railway
* Australia became 1,600 mm (5 ft 3 in) – Victoria & South Australia – partly converted to 1,435 mm (4 ft 8+1⁄2 in)
* India became 1,676 mm (5 ft 6 in) – initial freight lines
* some private Japanese railways

## Modern almost standard gauge railways

* The Toronto Transit Commission uses a Toronto gauge of 4 ft 10+7⁄8 in (1,495 mm) on its streetcar and heavy-rail subway lines, which was actually closer to 1,520 mm (4 ft 11+27⁄32 in) gauge.
** The Toronto Transit Commission light-metro lines and light-rail lines (whether existing, under construction or proposed) use standard gauge.
* Trams in Leipzig, Germany use 1,458 mm (4 ft 9+13⁄32 in).
* Trams in Dresden, Germany use 1,450 mm (4 ft 9+3⁄32 in).
* 1,445 mm (4 ft 8+7⁄8 in) gauge is in use on several urban rail transit systems in Europe:
** Trams in Italy
** Madrid Metro (only metro system. Light rail system uses standard gauge.)
* The MTR in Hong Kong uses 1,432 mm (4 ft 8+3⁄8 in) gauge on lines owned by the MTR Corporation. However, lines formerly operated (but which continue to be owned) by the Kowloon-Canton Railway Corporation, including the Light Rail network, use 1,435 mm (4 ft 8+1⁄2 in) gauge. New lines and extensions to the MTR after 2014 use 1,435 mm (4 ft 8+1⁄2 in) gauge, including the South Island line, Kwun Tong line extension and West Island line.
* The Bucharest Metro uses 1,432 mm (4 ft 8+3⁄8 in) gauge.
* The Washington Metro uses 4 ft 8+1⁄4 in (1,429 mm), 1⁄4 in (6 mm) narrower than standard gauge.
* The Mount Washington Cog Railway, the world's oldest mountain-climbing rack-and-pinion railway, uses a 4 ft 8 in (1,422 mm) gauge.

## Railways

| Country/territory | Railway | Notes |
| Albania | National rail network | 677 km (421 mi) |
| Algeria | National rail network Algiers Metro, Algiers tramway, Constantine tramway, Oran tramway, Oran Metro | 3,973 km (2,469 mi) |
| Angola | | 80 km (50 mi) |
| Argentina | General Urquiza Railway (except for Ferrocarril Económico Correntino, which used 600 mm or 1 ft 11+5⁄8 in before its closing) Buenos Aires Underground Metrotranvía Mendoza Tren de la Costa | Other major lines are mostly 1,676 mm (5 ft 6 in) broad gauge, with the exception of the 1,000 mm (3 ft 3+3⁄8 in) metre gauge General Belgrano Railway. Further information: Rail transport in Argentina |
| Australia | Australian Rail Track Corporation Pilbara Railways Sydney Trains Sydney Metro Sydney Light Rail Newcastle Light Rail Parramatta Light Rail NSW TrainLink Melbourne trams Adelaide Metro trams Gold Coast tram Canberra Metro Victorian Trains (Melbourne-Albury via Moonee Valley, Melbourne-Adelaide via Gerringhap, Dimboola, Rainbow Line Yelta Line, Maryborough- Mildura) Further information: List of Australian railway companies | Further information: Rail gauge in Australia 2,295 km (1,426 mi) Victoria built the first railways to the 5 ft 3 in (1,600 mm) 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 | Dhaka Metro Rail | 20.1 km (12.5 mi) |
| Belgium | NMBS/SNCB, Brussels Metro and tramway | NMBS/SNCB 3,619 km (2,249 mi) Brussels Metro 40 km (25 mi) Trams in Brussels 140 km (87 mi) |
| Bolivia | Mi Tren | 42 km (26.1 mi) |
| Bosnia and Herzegovina | Željeznice Federacije Bosne i Hercegovine and Željeznice Republike Srpske Sarajevo tramways | Further information: Rail transport in 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 1,435 mm and 1,000 mm or 3 ft 3+3⁄8 in metre gauge); 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) |
| Bulgaria | National Railway Infrastructure Company (NRIC) Bulgarian State Railways (BDZ) Sofia Underground part of Sofia Tramway system | |
| Canada | National rail network (including commuter rail operators like GO Transit, West Coast Express, Exo and Union Pearson Express). | 49,422 km (30,709 mi) The Toronto Transit Commission uses 4 ft 10+7⁄8 in (1,495 mm) gauge on its streetcar and subway lines. |
| China | National rail network | 103,144 km (64,091 mi) |
| Chile | Santiago Metro | 140.8 km (87 mi) |
| Croatia | Hrvatske željeznice | Further information: Transport in Croatia |
| Colombia | Metro de Medellín, Tren del Cerrejón, Metro de Bogotá | |
| Cuba | Ferrocarriles de Cuba | 4,266 km (2,651 mi) |
| Czech Republic | Správa železnic Prague Metro all tram systems in the country (Liberec has dual gauge 1,000/1,435 mm, with one metre-gauge only for heritage rolling stock on a small part of the network) funicular in Prague | 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. Cost studies have been undertaken for a potential overhaul of entire rail network to standard gauge. |
| Ethiopia | Addis Ababa-Djibouti Railway; Addis Ababa Light Rail | 659 km (409 mi) Other standard gauge lines under construction. |
| Finland | Tampere tram Helsinki–Tallinn Tunnel (planned) Rail Baltica (planned) | |
| France | SNCF, RATP (on RER lines) | |
| Gabon | Trans-Gabon Railway | 669 km (416 mi) |
| Germany | Deutsche Bahn, numerous local public transport providers | 43,468 km (27,010 mi) |
| Georgia | Georgian Railway 1,435 mm (4 ft 8+1⁄2 in) standard gauge constructed between Akhalkalaki to Karstakhi for Baku-Tbilisi-Kars Railway | 26.142 km (16.244 mi) |
| Ghana | Tema-Mpakadan Railway Line Takoradi to Sekondi Route, is currently operated by the Ghana Railway Company Limited. Kojokrom-Sekondi Railway Line (The Kojokrom-Sekondi line is a branch line that joins the Western Railway Line at Kojokrom) | New and extended SGR are being built, with some dual gauge. |
| 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, 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 |
| Hungary | MÁV, GySEV Budapest Metro HÉV (suburban railway) Tram systems in Budapest, Debrecen, Miskolc, Szeged Budapest Cog-wheel Railway Budapest Castle Hill Funicular | |
| 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 (Green Line), Lucknow Metro, Mumbai Metro, Nagpur Metro, Navi Mumbai Metro, Pune Metro and Trams in Kolkata. The under-construction Mumbai–Ahmedabad high-speed rail corridor based on the Shinkansen also uses standard gauge. All under-construction and future rapid transit systems would be in standard gauge.Delhi–Meerut Regional Rapid Transit System | 128,305 km (79,725 mi) Indian nationwide rail system (Indian Railways) uses 1,676 mm (5 ft 6 in) broad gauge. 96% of the broad gauge network is electrified. |
| Indonesia | Aceh rail, Bali MRT (under construction), Jakarta LRT, Jabodebek LRT, Trans-Sulawesi Railway (Makassar-Parepare section), Jakarta MRT West-east line (planned), and Jakarta-Bandung high speed networks | 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 railway tracks of Java and Sumatra use 1,067 mm (3 ft 6 in). |
| 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 Jerusalem Light Rail Tel Aviv Light Rail | |
| Italy | Ferrovie dello Stato | 16,723 km (10,391 mi) |
| Japan | Shinkansen, JR Hokkaido Naebo Works (see Train on Train), Sendai Subway (Tozai Line), Tokyo Metro (Ginza and Marunouchi lines), Toei Subway (Asakusa and Oedo lines), Yokohama Municipal Subway (Blue and Green lines), Nagoya Municipal Subway (Higashiyama, Meijō, and Meikō lines), Kyoto Municipal Subway, Osaka Metro, Kobe Municipal Subway, Fukuoka City Subway (Nanakuma Line), Keisei Electric Railway (including Hokusō and Shin-Keisei lines), Keikyu Line, Kintetsu Railway (Osaka, Nara, Nagoya, Yamada, Kyoto, and Keihanna lines and their associated branches), Keihan Railway, Hankyu Railway, Kita-Osaka Kyuko Railway, Nose Electric Railway, Hanshin Railway, Sanyo Electric Railway, Takamatsu-Kotohira Electric Railroad, Nishi-Nippon Railroad (Tenjin Ōmuta, Dazaifu and Amagi 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. |
| Kosovo | Trainkos | 437 km (272 mi) |
| Laos | Boten–Vientiane railway | 414 km (257 mi), Formally opened on 3 December 2021. |
| 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. The 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 | RapidKL (3 Ampang Line, 4 Sri Petaling Line, 5 Kelana Jaya Line, 9 MRT Kajang Line, 11 Shah Alam Line, 12 MRT Putrajaya Line) Express Rail Link (6 KLIA Express and 7 KLIA Transit)  ECR MRL East Coast Rail Link (under construction)  HSR Kuala Lumpur–Singapore High Speed Rail (planned) | 998 km (620 mi) |
| Mexico | Further information: List of Mexican railroads | 24,740 km (15,370 mi) |
| Monaco | | |
| Montenegro | Željeznice Crne Gore | 3 |
| Morocco | Rail transport in Morocco | 2,067 km (1,284 mi) |
| Nepal | Nepal Railways (all tracks except cross-border tracks with India are standard gauge) | Under-construction |
| Netherlands | Nederlandse Spoorwegen and regional railways. | |
| 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 the rapid transit system, Lahore Metro | Pakistan's nationwide rail system (Pakistan Railways) uses 1,676 mm (5 ft 6 in) broad gauge. Any future additions to this system would also be in broad gauge. |
| Panama | Panama Railway; Panama Metro | Regauged from 5 ft (1,524 mm) 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 | Operational: LRT 1, LRT 2, and MRT 3. Under construction: MRT 7, MRT 4, LRT 1 South/Cavite Extension, MMS, PNR SLH, PNR NSCR, and Mindanao Railway Phase 1. All current as of March 2022. | 54.15 km (33.65 mi) operational, 899.6 km (559.0 mi) under construction, all electrified as of March 2022. |
| Philippines | 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. |
| Poland | Polskie Koleje Państwowe, Warsaw Metro, most tramway systems throughout the country | |
| Portugal | Braga and Porto (Guindais) funiculars, Lisbon Metro, Porto Metro (partly adapted from former 1,000 mm (3 ft 3+3⁄8 in) metre gauge; tracks), Metro Transportes do Sul light rail in Almada. | All other railways use 1,668 mm (5 ft 5+21⁄32 in) (broad gauge); some use 1,000 mm (3 ft 3+3⁄8 in) metre gauge; Decauville uses 500 mm (19+3⁄4 in) gauge. Planned and under construction high-speed railways to use 1,668 mm (5 ft 5+21⁄32 in) to maintain interoperability with the rest of the network. |
| Romania | Căile Ferate Române Bucharest Metro Tram systems in Botoșani, Brăila, Bucharest, Cluj-Napoca, Craiova, Galați, Ploiești and Timișoara | |
| 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 | |
| Senegal | Train Express Regional Dakar-AIBD Senegal–Gambia Railway (planned) Senegal–Guinea Bissau Railway (planned) | |
| Serbia | Serbian Railways | |
| Singapore | Mass Rapid Transit | 203 km (126 mi) |
| Slovakia | Železnice Slovenskej republiky, Košice tramway system | |
| Slovenia | Slovenske železnice | |
| South Africa | Gautrain in Gauteng Province. Rest of country uses 1,067 mm (3 ft 6 in) | 80 km (50 mi) |
| South Korea | KRNA | |
| Spain | AVE high-speed rail lines from Madrid to Seville, Málaga, Alicante, Saragossa, Barcelona (-Perthus), Orense, Toledo, Huesca, León 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 1,668 mm (5 ft 5+21⁄32 in) (broad gauge) and/or 1,000 mm (3 ft 3+3⁄8 in) metre gauge. | 3,622 km (2,251 mi) |
| Sweden | Swedish Transport Administration, Storstockholms Lokaltrafik (Stockholm metro, commuter and light rail lines), tram networks in Gothenburg, Lund and Norrköping | |
| Switzerland | Swiss Federal Railways, BLS, Rigi Railways (rack railway) | SFR 3,134 km in standard gauge and 98 km metre gauge 449 km |
| Syria | Chemins de Fer Syriens | 2,052 km (1,275 mi) |
| Taiwan | Taiwan High Speed Rail Taipei Rapid Transit System, Kaohsiung Mass Rapid Transit, Taoyuan Airport MRT and Taichung Metro Kaohsiung Circular light rail and Danhai light rail | 604.64 km (376 mi) |
| Tanzania | Tanzania Standard Gauge Railway | 300 km (186 mi) line from Dar es Salaam to Morogoro has been completed in April 2022 currently in live testing phase. Contract awarded in 2019 for a 422 km (262 mi) extension from Morogoro to Makutupora. |
| Thailand | BTS Skytrain, MRT, and Suvarnabhumi Airport Link The State Railway of Thailand uses 1,000 mm (3 ft 3+3⁄8 in). | 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 1,000 mm (3 ft 3+3⁄8 in) metre gauge. Further information: Rail transport in Turkey |
| 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 4 ft (1,219 mm). |
| United States | Modern national railroad network; see Track gauge in the United States The Washington Metro uses 4 ft 8+1⁄4 in (1,429 mm) gauge, which is 6 mm (0.24 in) narrower than standard gauge. The Bay Area Rapid Transit system uses 5 ft 6 in (1,676 mm). The San Francisco cable car system uses 3 ft 6 in (1,067 mm). | 129,774 km (80,638 mi) |
| Uruguay | National rail network | 2,900 km (1,800 mi) |
| Vietnam | North of Hanoi Hanoi Metro Ho Chi Minh City Metro | 178 km (111 mi). Includes dual gauge (standard/metre) to the Chinese border. |

## Non-rail use

Several states in the United States had laws requiring road vehicles to have a consistent gauge to allow them to follow ruts in the road. Those gauges were similar to railway standard gauge.