|By transport mode|
|By size ( list)|
|Change of gauge|
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 and European gauge in Europe,      and SGR in East Africa. 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 1435.1 mm.
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 1,435 mm (4 ft 8+1⁄2 in), allowing interconnectivity and interoperability.
A popular legend that has been around 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. [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 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 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". [ better source needed]
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),[ citation needed] 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 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).  
The 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. 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 to the 1,435 mm (4 ft 8+1⁄2 in) 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 used 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 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 standard 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.
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). 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 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, according to the "Revue générale des chemins de fer, July 1928".
- Monkland and Kirkintilloch Railway, authorised 1824 and opened 1825, used 4 ft 6 in (1,372 mm).
- Dundee and Newtyle Railway, authorised 1829 and opened 1831, used 4 ft 6+1⁄2 in (1,384 mm).
- The Eastern Counties Railway, authorised on 4 July 1836, used 5 ft (1,524 mm) 
- The London and Blackwall Railway, authorised on 28 July 1836, used 5 ft 1⁄2 in (1,537 mm).   
- The Dundee and Arbroath Railway, incorporated on 19 May 1836 and opened October 1838, used 5 ft 6 in (1,676 mm) until standardised in 1847.
- The Arbroath and Forfar Railway, incorporated on 19 May 1836 and opened November 1838, used 5 ft 6 in (1,676 mm).
- The Northern and Eastern Railway, authorised on 4 July 1836, used 5 ft (1,524 mm) gauge. 
- Aberdeen Railway, opened 1848, used 5 ft 6 in (1,676 mm) until standardised.
- 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.
- The Baltimore and Ohio Railroad, begun 1827, opened 1830.
- The Liverpool and Manchester Railway, authorised 1824, opened 1830.
- The Saint-Étienne–Lyon railway, authorised 1826, opened 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)
- The Dublin and Kingstown Railway, authorised 1831, opened for passenger traffic 1834.
- The Newcastle & Carlisle Railway, authorised 1829, opened 1834, isolated from LMR.
- The Grand Junction Railway, authorised 1833, opened 1837, connected to LMR.
- The London and Birmingham Railway, authorised 1833, opened 1838, connected to LMR.
- The Manchester and Birmingham Railway, authorised 1837, opened 1840, connected to LMR.
- The Birmingham and Gloucester Railway, authorised 1836, opened 1840, connected to LMR.
- The London and Southampton Railway, authorised 1834, opened 1840.
- The London and Brighton Railway, authorised 1837, opened 1841.
- The South Eastern Railway, authorised 1836, opened 1844.
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 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)
- 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).
- 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.
- 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:
- 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.
|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 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.|
1,435 mm (4 ft 8+1⁄2 in) 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||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 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)|
|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)|
|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 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||G-Rail||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, 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 1,676 mm (5 ft 6 in) 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 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, 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, Meijō, and Meikō 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||Željeznice Crne Gore||3|
|Morocco||Rail transport in Morocco||2,067 km (1,284 mi)|
|Myanmar||Kunming China- Kyaukpyu Myanmar Railway||Opened in 2021|
|Nepal||Nepal Railways (all tracks except cross-border tracks with India are standard gauge)||Under-construction|
|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 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||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 Państwowe, 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 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.|
|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||Železnice Slovenskej republiky, Košice tramway system|
|South Africa||Gautrain in Gauteng Province. Rest of country uses 1,067 mm (3 ft 6 in)||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)||2,571 km (1,598 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,||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 1,000 mm (3 ft 3+3⁄8 in) metre gauge.|
|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||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.|
- Standard Gauge (toy trains)
- List of track gauges § Standard gauge
- List of tram systems by gauge and electrification
- Track gauge
- Regulating the Gauge of Railways Act 1846
- The gaps in the pedestrian crossings in Pompeii could give credence or otherwise to this statement, but no relevant studies appear to have been made.
- For the Philippine National Railways, 2,278 km (1,415 mi) for the Mindanao Railway, 296 km (184 mi) for the North–South Commuter Railway (NSCR),  298 km (185 mi) for NSCR extensions,  92 km (57 mi) for the Norteast Commuter Line to Cabanatuan,   581 to 639 km (361 to 397 mi) for the South Main Line rehabilitation, 71 km (44 mi) for the Subic–Clark Railway, 244 km (152 mi) for the San Jose– Tuguegarao line,  and 175 km (109 mi) for the Tarlac–San Fernando line.  Proposed MRT lines have a total length of 370 km (230 mi), discounting the Monorail Line 4. LRT Line 1 extension is 26 km (16 mi),  while LRT Line 6's total proposed track length is 169 km (105 mi).  All figures mentioned denote track length, not line or system length.
- Falco, Francesco (31 December 2012). "2007-ee-27010-s". TEN-T Executive Agency. Archived from the original on 27 February 2012. Retrieved 20 August 2013.
- "Japan". Speedrail.ru. 1 October 1964. Archived from the original on 29 June 2012. Retrieved 20 August 2013.
- Falco, Francesco (23 January 2013). "EU support to help convert the Port of Barcelona's rail network to UIC gauge". TEN-T Executive Agency. Archived from the original on 11 February 2013. Retrieved 20 August 2013.
- "Spain: opening of the first standard UIC gauge cross-border corridor between Spain and France". UIC Communications. Retrieved 20 August 2013.
- "Displaceable rolling bogie for railway vehicles". IP.com. Archived from the original on 29 June 2013. Retrieved 20 August 2013.
-  Thirty-Seventh Congress Session III Chap CXII March 3, 1863 Retrieved on 2019-01-08.
- "Standard Railway Gauge". Townsville Bulletin. 5 October 1937. p. 12. Retrieved 3 June 2011 – via National Library of Australia.
- "Standard Rail Gauge Set By Old Ox-Carts". The Worker. 58 (3122). Queensland. 19 May 1947. p. 17. Retrieved 13 April 2016 – via National Library of Australia.
- "Railroad Gauges and Roman Chariots". Snopes.com.
- Ogata et al. (2006), p. 98
- 1966, p. 56 harvnb error: no target: CITEREF1966 ( help).
- Baxter 1966, p. 56.
- "Tyne and Wear HER(1128): Bigges Main Wagonway - Details". TWsitelines.info. Archived from the original on 21 November 2016. Retrieved 20 November 2016.
- "The Wagons". DRCM. Retrieved 1 June 2016.
- Vaughan (1997).[ page needed]
- Vaughan 1977. sfn error: no target: CITEREFVaughan1977 ( help)
- "Trans-Australian Railway. Bill Before The Senate". Western Mail (Western Australia). Perth. 2 December 1911. p. 17. Retrieved 15 March 2013 – via National Library of Australia.
- "Peoples' Liberal Party". Bendigo Advertiser. 27 February 1912. p. 5. Retrieved 21 November 2013 – via National Library of Australia.
- Jones (2009), pp. 64–65.
- "The Days They Changed the Gauge". Retrieved 1 June 2016.
- Auguste Perdonnet, mémoire sur les chemins à ornières, 1830
- Whishaw (1842), p. 91.
- "Public transport in and about the parish". St George-in-the-East Church. London. London and Blackwall Railway; London, Tilbury & Southend Railway.
- "Docklands Light Railway: Tower Gateway to West India Quay" (PDF). Mernick. Retrieved 1 June 2016.
- Whishaw (1842), p. 260.
- Whishaw (1842), p. 363.
- Jones (2013), p. 33.
- Whishaw (1842), p. 319.
- Whishaw (1842), p. 54.
- Whishaw (1842), p. 273.
- Whishaw (1842), p. 303.
- "Albania". The World Factbook. Retrieved 1 June 2016.
- "CIA data".
- "Algeria". The World Factbook. Retrieved 1 June 2016.
- Setti (2008), p. 25.
- "Metropolitan Sofia". Metropolitan.bg. Archived from the original on 18 August 2009. Retrieved 7 December 2011.
- "Sofia Public Transport Co". Archived from the original on 10 August 2006. Retrieved 1 June 2016.
- "香港鐵路(MTR)". 2427junction.com. 15 February 2006. Retrieved 20 August 2013.
- "Hong Kong's MTR System". Roof and Facade. 12 March 2007. Archived from the original on 9 June 2013. Retrieved 7 December 2011.
- Allen (1987).[ page needed]
- "History of Railways in Indonesia". keretapi.tripod.com. Retrieved 25 May 2021.
- "Nederlands-Indische Spoorweg Maatschappij". searail.malayanrailways.com. Retrieved 25 May 2021.
- "Mexlist". 2007. Retrieved 29 November 2007.
- "SECTION - 3 DESCRIPTION OF THE PROJECT" (PDF). EIA of Construction of Lahore Orange Line Metro Train Project (Ali Town –Dera Gujran). Environmental Protection Department. Retrieved 25 January 2017.
- "Ferrocarril Central Andino". Railroad Development Corporation. 2007. Retrieved 29 November 2007.
- "Philippines approves standard gauge for all new lines". 10 August 2016. Retrieved 12 July 2020.
- "Biz sector calls on gov't. to prioritize Mindanao railway system". Philippine Information Agency. 27 November 2018. Retrieved 20 April 2021.
- Dela Paz, Chrisee (13 September 2017). "NEDA Board approves Metro Manila Subway". Rappler. Retrieved 14 September 2017.
- TECHNICAL REPORT NO. 3: URBAN / TRANSPORTATION DEVELOPMENT CONDITION IN ADJOINING AREAS (PDF). METRO MANILA URBAN TRANSPORTATION INTEGRATION STUDY (Report). Japan International Cooperation Agency. Retrieved 21 April 2021.
- Villanueva, Joann (22 January 2019). "PNR asks for feasibility of Cabanatuan-Makati line". Philippine News Agency. Retrieved 2 August 2020.
- "CEZA pursuing expressway, railway projects in Cagayan". Philippine News Agency. Retrieved 28 June 2020.
- "Bidding Documents – Preliminary Works for the Subic–Clark Railway Project" (PDF). Bases Conversion and Development Authority. Archived from the original (PDF) on 26 June 2020. Retrieved 21 April 2021.
- Cordero, Ted (4 July 2018). "Tugade says LRT1 Cavite extension to be completed in 2021". GMA News Online. Retrieved 8 July 2018.
- "Project Description for Scoping (Line 6A and 6B/C)" (PDF). Environmental Management Bureau, Department of Environment and Natural Resources. 31 January 2019. Retrieved 18 February 2021.
- "Infrastructures". SBB/CFF/FFS. 2018. Retrieved 21 July 2019.
- "Railway Infrastructure". Vietnam Railways. 2005. Archived from the original on 18 April 2010. Retrieved 29 November 2007.
- "The Narrow-Gauge Question". The Argus. Melbourne. 2 October 1872. Retrieved 14 April 2012 – via Trove.nla.gov.au.
- Allen, Geoffrey Freeman (1987). Jane's World Railways, 1987–88. Jane's Information. ISBN 978-0-71060848-2.
- Baxter, Bertran (1966). Stone Blocks and Iron Rails (Tramroads). Industrial Archaeology of the British Isles. Newton Abbot: David & Charles. ISBN 978-0-715340-04-2. OCLC 643482298.
- Jones, Robin (2013). The Rocket Men. Mortons Media. ISBN 978-1-90912827-9.
- Jones, Stephen K (2009). Brunel in South Wales. II: Communications and Coal. Stroud: The History Press. pp. 64–65. ISBN 978-0-75244912-8.
- Ogata, Masanori; Tsutsumi, Ichiro (2006). "Origin of the world's standard gauge of railway is in the interval of wheel ruts of ancient carriages". The International Conference on Business & Technology Transfers. 2006 (3): 98–103. doi: 10.1299/jsmeicbtt.2006.3.0_98. Retrieved 23 June 2020.
- Pomeranz, Kenneth; Topik, Steven (1999). The World that Trade Created: Society, Culture, and World Economy, 1400 to the Present. Armonk, NY: M.E. Sharpe. ISBN 978-0-7656-0250-3.
- Puffert, Douglas J (2009). Tracks across Continents, Paths through History: The Economic Dynamics of Standardization in Railway Gauge. University of Chicago Press. ISBN 978-0-226-68509-0.
- Setti, João Bosco (2008). Brazilian Railroads. Rio de Janeiro: Memória do Trem. ISBN 978-85-8609409-5 – via Google Books.
- Vaughan, A. (1997). Railwaymen, Politics and Money. London: John Murray. ISBN 978-0-7195-5150-5.
- Whishaw, Francis (1969) [1842, John Weale]. The Railways of Great Britain and Ireland: Practically Described and Illustrated. London: David & Charles; reprints: Newton Abbot. ISBN 978-0-7153-4786-7.
- "The Sydney Morning Herald". The Sydney Morning Herald. 23 May 1892. p. 4. Retrieved 14 August 2011 – via National Library of Australia., a discussion of gauge in Australia circa 1892
- "Standard Railway Gauge". Townsville Bulletin. 5 October 1937. p. 12. Retrieved 19 March 2014 – via National Library of Australia., a discussion of the Roman gauge origin theory.