NomenclatureA narrow-gauge railway is one where the distance between the inside edges of the rails is less than . Historically, the term was sometimes used to refer to standard-gauge railways, to distinguish them from broad-gauge railways, but this use no longer applies.
Early hand-worked lines'', showing a narrow-gauge railway in a mine The earliest recorded railway appears in Georgius Agricola's 1556 ''De re metallica'', which shows a mine in Bohemia with a railway of about gauge. During the 16th century, railways were primarily restricted to hand-pushed, narrow-gauge lines in mines throughout Europe. In the 17th century, mine railways were extended to provide transportation above ground. These lines were industrial railway, industrial, connecting mines with nearby transportation points (usually canals or other waterways). These railways were usually built to the same narrow gauge as the mine railways from which they developed.
Introduction of steamThe world's first steam locomotive, built in 1802 by Richard Trevithick for the Coalbrookdale Company, ran on a plateway. The first commercially successful steam locomotive was Matthew Murray's Salamanca (locomotive), Salamanca built in 1812 for the Middleton Railway in Leeds. Salamanca was also the first Rack railway, rack-and-pinion locomotive. During the 1820s and 1830s, a number of industrial narrow-gauge railways in the United Kingdom used steam locomotives. In 1842, the first narrow-gauge steam locomotive outside the UK was built for the -gauge Antwerp-Ghent Railway in Belgium. The first use of steam locomotives on a public, passenger-carrying narrow-gauge railway was in 1865, when the Ffestiniog Railway introduced passenger service after receiving its first locomotives two years earlier.
Industrial useMany narrow-gauge railways were part of industrial enterprises and served primarily as industrial railways, rather than general carriers. Common uses for these industrial narrow-gauge railways included mining, logging, construction, tunnelling, quarrying, and conveying agricultural products. Extensive narrow-gauge networks were constructed in many parts of the world; 19th-century mountain logging operations often used narrow-gauge railways to transport logs from mill to market. Significant sugarcane railways still operate in Cuba, Fiji, Java, the Philippines, and Queensland, and narrow-gauge railway equipment remains in common use for building tunnels.
Introduction of internal-combustionIn 1897, a manganese mine in the Lahn valley in Germany was using two benzine-fueled locomotives with single cylinder internal combustion engines on the 500mm gauge tracks of their mine railway; these locomotives were made by the Deutz Gas Engine Company (''Gasmotorenfabrik Deutz''), now Deutz AG. Another early use of internal combustion was to power a narrow-gauge locomotive was in 1902. Francis Claude Blake, F. C. Blake built a 7 hp petrol locomotive for the Richmond Main Sewerage Board sewage plant at Mortlake. This gauge locomotive was probably the third petrol-engined locomotive built.
First World War and laterExtensive narrow-gauge trench railways, rail systems served the front-line trenches of both sides in World War I. They were a short-lived military application, and after the war the surplus equipment created a small boom in European narrow-gauge railway building.
Heavy-duty tracksThe heavy-duty narrow-gauge railways in , South Africa, and New Zealand demonstrate that if track is built to a heavy-duty standard, performance almost as good as a standard-gauge line is possible. Two-hundred-car trains operate on the Sishen–Saldanha railway line in South Africa, and high-speed Tilt Trains run in Queensland. In South Africa and New Zealand, the loading gauge is similar to the restricted British loading gauge; in New Zealand, some New Zealand British Rail Mark 2 carriage, British Rail Mark 2 carriages have been Bogie exchange, rebuilt with new bogies for use by Tranz Scenic (Wellington-Palmerston North service), Tranz Metro (Wellington-Masterton service), and Transdev Auckland (Auckland suburban services). Another example of a heavy-duty narrow-gauge line is Brazil's Vale (company)#Railroads, EFVM. gauge, it has Rail profile#North America, over-100-pound rail () and a Loading gauge#North America, loading gauge almost as large as US non-excess-height lines. The line has a number of locomotives and 200-plus-car trains.
Fastest trainsNarrow gauge's reduced stability means that its trains cannot run at speeds as high as on broader gauges. For example, if a curve with standard-gauge rail can allow speed up to , the same curve with narrow-gauge rail can only allow speed up to . In Japan and Queensland, recent permanent-way improvements have allowed trains on gauge tracks to exceed . Queensland Rail's QR Tilt Train, Electric Tilt Train, the fastest train in Australia and the fastest gauge train in the world, set a record of . The speed record for narrow-gauge rail is , set in South Africa in 1978. A special gauge railcar was built for the Otavi Mining and Railway Company with a design speed of 137 km/h. Curve radius is also important for high speeds: narrow-gauge railways allow sharper curves, but these limit a vehicle's safe speed.
GaugesMany narrow gauges, from gauge and gauge, are in present or former use. They fall into several broad categories:
Just under standard gauge
* Huddersfield Corporation Tramways * Glasgow Corporation Tramways
4 ft 6 in gaugetrack gauge (also known as Scotch gauge) was adopted by early 19th-century railways, primarily in the Lanarkshire area of Scotland. lines were also constructed, and both were eventually converted to standard gauge.
Around 4 ft gauge
* Middleton Railway
* City of Oxford Tramways Company * Glasgow Subway * Padarn Railway * Bradford Corporation Tramways * Keighley Tramways * Wellington tramway system * Saundersfoot Railway * Derby Tramways Company * Reading Corporation Tramways * Barrow-in-Furness Tramways Company * Darwen Corporation Tramways * Honolulu Rapid Transit and Land Company
* Central Funicular * Gardena Ronda Express * Zagreb Funicular#Technical characteristics, Zagreb Funicular * Rheineck–Walzenhausen mountain railway, Appenzell Railways#Operation, Appenzell Railways * Schlossbergbahn (Freiburg) * Stoosbahn
3 ft 7 in gauge
3 ft 6 in gaugebetween the inside of the rail heads, its name and classification vary worldwide and it has about of track.
Similar gauges* in Rail transport in Algeria, Algeria * on the Hejaz railway in Israel, Jordan, Lebanon, Saudi Arabia and Syria; only a few lines survive.
Metre gauge and Italian metre gaugeAs its name implies, metre gauge is a track gauge of . It has about of track. According to Italian law, track gauges in Italy were defined from the centre of each rail rather than the inside edges of the rails. This gauge, measured between the edges of the rails, is known as Track gauge in Italy, Italian metre gauge.
3 ft, 900 mm, and Swedish three foot gaugein California There were a number of large railroad systems in North America; notable examples include the Denver & Rio Grande and Rio Grande Southern Railroad, Rio Grande Southern in Colorado and the South Pacific Coast Railroad, South Pacific Coast and West Side Lumber Company railway, West Side Lumber Co of California. was also a common track gauge in South America, Ireland and on the Isle of Man. was a common gauge in Europe. Swedish three-foot-gauge railways () are unique to that country.
2 ft 9 in gaugeA few railways and tramways were built to gauge, including Nankai Main Line (later Track gauge conversion, converted to ), Ocean Pier Railway at Atlantic City, Seaton Tramway (converted from ) and Waiorongomai Tramway.
800 mm, 2 ft 6 in, Bosnian and 750 mm gaugegauge railways are commonly used for rack railways. Imperial gauge railways were generally constructed in the former British colonies. Bosnian gauge and railways are predominantly found in Russia and Eastern Europe.
Between 2 ft 1 in and 2 ft 5 in gaugeGauges such as , and were used in parts of the UK, particularly for railways in Wales and the borders, with some industrial use in the coal industry. Some sugar cane lines in Cuba were .
2 ft and 600 mm gaugesImage:Ffestiniog DLG BF.JPG, alt=Red locomotive, with observers on a platform, The gauge Ffestiniog Railway in Wales gauge railways were generally constructed in the former British colonies. , and were used in Europe.
Minimum gaugeGauges below were rare. Arthur Percival Heywood developed gauge British narrow-gauge railways#Estate railways, estate railways in Britain and Decauville produced a range of industrial railways running on and tracks, most commonly in restricted environments such as underground mine railways, parks and farms, in France. Several gauge railways were built in Britain to serve ammunition depots and other military facilities, particularly during World War I.
See also* Feldbahn * Forest railway * Heeresfeldbahn * List of track gauges#Narrow gauge, List of track gauges * List of tram systems by gauge and electrification * Military railways * Narrow-gauge railway modelling * Rail transport in Walt Disney Parks and Resorts * Ridable miniature railway * Track gauge * Trench railways * War Department Light Railways