In rail transport, track gauge is the distance between the two rails of a railway track. All vehicles on a rail network must have wheelsets that are compatible with the track gauge. Since many different track gauges exist worldwide, gauge differences often present a barrier to wider operation on railway networks.
The term derives from the metal bar, or gauge, that is used to ensure the distance between the rails is correct.
Railways also deploy two other gauges to ensure compliance with a required standard. A loading gauge is a two-dimensional profile that encompasses a cross-section of the track, a rail vehicle and a maximum-sized load: all rail vehicles and their loads must be contained in the corresponding envelope. A structure gauge specifies the outline into which structures (bridges, platforms, lineside equipment etc.) must not encroach.
As the guidance of the wagons was improved, short strings of wagons could be connected and pulled by teams of horses, and the track could be extended from the immediate vicinity of the mine or quarry, typically to a navigable waterway. The wagons were built to a consistent pattern and the track would be made to suit the needs of the horses and wagons: the gauge was more critical. The Merthyr Tramroad of 1802 in South Wales, a plateway, spaced these at over the outside of the upstands.R. Cragg (1997), Civil Engineering Heritage – Wales and West Central, Thomas Telford Publishing, London, 2nd edition, England,
The Penydarren Tramroad probably carried the first journey by a locomotive, in 1804, and it was successful for the locomotive, but unsuccessful for the track: the plates were not strong enough to carry its weight. A considerable progressive step was made when cast iron edge rails were first employed; these had the major axis of the rail section configured vertically, giving a much stronger section to resist bending forces, and this was further improved when fish-belly rails were introduced.Andy Guy and Jim Rees, Early Railways 1569–1830, Shire Publications in association with the National Railway Museum, Oxford, 2011,
Edge rails required a close match between rail spacing and the configuration of the wheelsets, and the importance of the gauge was reinforced. Railways were still seen as local concerns: there was no appreciation of a future connection to other lines, and the choice of track gauge was still a pragmatic decision based on local requirements and prejudices, and probably determined by existing local designs of (road) vehicles.
Thus, the Monkland and Kirkintilloch Railway (1826) in the West of Scotland used ;Don Martin, The Monkland and Kirkintilloch and Associated Railways, Strathkelvin Public Libraries, Kirkintilloch, 1995, the Dundee and Newtyle Railway (1831) in the north-east of Scotland adopted ;N. Ferguson (1995), The Dundee and Newtyle Railway including the Alyth and Blairgowrie Branches, The Oakwood Press, . the Redruth and Chasewater Railway (1825) in Cornwall chose .D. B. Barton (1966), The Redruth and Chasewater Railway, 1824–1915, D. Bradford Barton Ltd, Truro, 2nd edition
The Arbroath and Forfar Railway opened in 1838 with a gauge of ,Francis Whishaw, The Railways of Great Britain and Ireland Practically Described and Illustrated, 1842, reprint 1969, David & Charles (Publishers) Limited, Newton Abbot, and the Ulster Railway of 1839 used .
The Stockton and Darlington line was very successful, and when the Liverpool and Manchester Railway, the first intercity line, was opened in 1830, it used the same gauge. It too was very successful, and the gauge, widened to and named "standard gauge", was well on its way to becoming the established norm.
At the same time, other parts of Britain built railways to standard gauge, and British technology was exported to European countries and parts of North America, also using standard gauge. Britain polarised into two areas: those that used Brunel gauge and those that used standard gauge. In this context, standard gauge was referred to as "narrow gauge" to indicate the contrast. Some smaller concerns selected other non-standard gauges: the Eastern Counties Railway adopted . Most of them converted to standard gauge at an early date, but the GWR's broad gauge continued to grow.
The larger railway companies wished to expand geographically, and large areas were considered to be under their control. When a new independent line was proposed to open up an unconnected area, the gauge was crucial in determining the allegiance that the line would adopt: if it was broad gauge, it must be friendly to the Great Western railway; if narrow (standard) gauge, it must favour the other companies. The battle to persuade or coerce that choice became very intense, and became referred to as Gauge War.
As passenger and freight transport between the two areas became increasingly important, the difficulty of moving from one gauge to the other—the break-of-gauge—became more prominent and more objectionable. In 1845 a Royal Commission on Railway Gauges was created to look into the growing problem, and this led to the Regulating the Gauge of Railways Act 1846, which forbade the construction of broad gauge lines unconnected with the broad gauge network. The broad gauge network was eventually converted—a progressive process completed in 1892, called gauge conversion. The same Act mandated the gauge of for use in Ireland.
In British practice, the space between the rails of a track is colloquially referred to as the "four-foot", and the space between two tracks the "six-foot", descriptions relating to the respective dimensions.
Broad gauge is the dominant gauge in countries in Indian subcontinent, the former Soviet Union (CIS states, Baltic states, Georgia and Ukraine), Mongolia, Finland, Spain, Portugal, Argentina, Chile and Ireland. It is also used for the suburban railway systems in South Australia, and Victoria, Australia.
In 1840s, the Irish gauge was considered a medium gauge compared to Brunel's broad gauge and the narrow gauge, which became the modern standard gauge.
Narrow gauge is the dominant or second dominant gauge in countries of Southern, Central Africa, East Africa, Southeast Asia, Japan, Taiwan, Philippines, Central America and South America,
During the period known as "the Battle of the gauges", Stephenson's standard gauge was commonly known as "narrow gauge", while Brunel's railway's gauge was termed "broad gauge". Many narrow gauge railways were built in mountainous regions such as Wales, the Rocky Mountains of North America, Central Europe and South America. Industrial railways and across the world are often narrow gauge. Sugar cane and banana plantations are mostly served by narrow gauges.
On narrow gauge lines, or transporter wagons are used: standard gauge wagons are carried on narrow gauge lines on these special vehicles, generally with rails of the wider gauge to enable those vehicles to roll on and off at transfer points.
On the Transmongolian Railway, Russia and Mongolia use while China uses the standard gauge of 1,435 mm. At the border, each carriage is lifted and its Bogie exchange. The operation can take several hours for a whole train of many carriages.
Other examples include crossings into or out of the former Soviet Union: Ukraine/Slovakia border on the Bratislava–Lviv train, and the Romania/Moldova border on the Chișinău–Bucharest train.
A system developed by Talgo and Construcciones y Auxiliar de Ferrocarriles (CAF) of Spain uses variable gauge wheelsets; at the border between France and Spain, Through service are drawn slowly through an apparatus that alters the gauge of the wheels, which slide laterally on the axles.Alberto García Álvarez, "Automatic Gauge Changeover for Trains in Spain" (PDF), Fundación de los Ferrocarrilos Españoles, 2010.
A similar system is used between China and Central Asia, and between Poland and Ukraine, using the SUW 2000 and INTERGAUGE variable axle systems. China and Poland use standard gauge, while Central Asia and Ukraine use .
Tracks of multiple gauges involve considerable costs in construction (including signalling work) and complexities in track maintenance, and may require some speed restrictions. They are therefore built only when absolutely necessary. If the difference between the two gauges is large enough – for example between and – three-rail dual-gauge is possible, but if not – for example between and – four rails must be used. Dual-gauge rail lines occur (or have occurred) in Argentina, Australia, Brazil, Japan, North Korea, Spain, Switzerland, Tunisia and Vietnam.
On the GWR, there was an extended period between political intervention in 1846 that prevented major expansion of its broad gaugeThe Act of Parliament did not prohibit expansion of the existing broad gauge system, but it had the indirect and delayed effect of forcing conformity with the "standard" gauge eventually. and the final gauge conversion to standard gauge in 1892. During this period, many locations practicality required mixed gauge operation, and in station areas the track configuration was extremely complex. This was compounded by the common rail having to be at the platform side in stations; therefore, in many cases, standard-gauge trains needed to be switched from one side of the track to the other at the approach. A special fixed point arrangement was devised for the purpose, where the track layout was simple enough.
In some cases, mixed gauge trains were operated with wagons of both gauges. For example, MacDermotE. T. MacDermot (1931), History of the Great Western Railway, vol. II: 1863–1921, London: Great Western Railway, p. 316 wrote:
Rolling stock on the network must have running gear (wheelsets) that are compatible with the gauge, and therefore the gauge is a key parameter in determining interoperability, but there are many others – see below. In some cases in the earliest days of railways, the railway company saw itself as an infrastructure provider only, and independent hauliers provided wagons suited to the gauge. Colloquially the wagons might be referred to as "four-foot gauge wagons", say, if the track had a gauge of four feet. This nominal value does not equate to the flange spacing, as some freedom is allowed for.
An infrastructure manager might specify new or replacement track components at a slight variation from the nominal gauge for pragmatic reasons.
Imperial units were established in the United Kingdom by the Weights and Measures Act 1824. The United States customary units for length did not agree with the imperial system until 1959, when one international yard was defined as 0.9144 meters and, as derived units, 1 foot (= yd) as 0.3048 meter and 1 inch (= yd) as 25.4 mm.
The list shows the imperial and other units that have been used for track gauge definitions:
In restricted spaces such as tunnels, the temporary way might be double track even though the tunnel will ultimately be single track. The Airport Rail Link in Sydney had construction trains of gauge, which were replaced by permanent tracks of gauge.
During World War I, trench warfare led to a relatively static disposition of infantry, requiring considerable logistics to bring them support staff and supplies (food, ammunition, earthworks materials, etc.). Dense light railway networks using temporary narrow gauge track sections were established by both sides for this purpose.Christian Wolmar, Engines of War: How Wars Were Won & Lost on the Railways, Atlantic Books, London, 2010,
In 1939 it was proposed to construct the western section of the Yunnan–Burma Railway using a gauge of , since such tiny or "toy" gauge facilitates the tightest of curves in difficult terrain.
For temporary railways which will be removed after short-term use, such as those used in logging, mining or large-scale construction projects, especially in confined spaces, such as when constructing the Channel Tunnel, a narrow-gauge railway is substantially cheaper and easier to install and remove. Such railways have almost vanished due to the capabilities of modern . In many countries, narrow-gauge railways were built as branch lines to feed traffic to standard-gauge lines due to lower construction costs. The choice was often not between a narrow- and standard-gauge railway, but between a narrow-gauge railway and none at all.
Broader gauge railways are generally more expensive to build, because they are usually heavier in construction, use larger railway car and (larger loading gauge), as well as larger , larger (larger structure gauge). But broader gauges offer higher speed and capacity. For routes with high traffic, greater capacity may more than offset the higher initial cost of construction.
Since adopting a new standard is difficult and expensive, continuing with an existing standard can remain attractive, unless longer-term benefits are given appropriate weight. An example of the consequences of path dependence is the persistence in the United Kingdom – the earliest nation to develop and adopt railway technologies – of that are too small to allow the larger rolling stock of continental Europe to operate in the UK. The reduced cost, greater efficiency, and greater economic opportunity offered by the use of a common standard has resulted in the historical multitude of track gauges dwindling to a small number that predominate worldwide.
When interchangeability has not been achieved, freight and passengers must be transferred through time-consuming procedures requiring manual labour and substantial capital expenditure. Some bulk commodities, such as coal, ore, and gravel, can be mechanically Transshipment, but even this is time-consuming, and the equipment required for the transfer is often complex to maintain. If rail lines of different gauges coexist in a network and a break of gauge exists, it is difficult in times of peak demand to move rolling stock to where it is needed.
Sufficient rolling stock must be available to meet a narrow-gauge railway's peak demand, which might be greater in comparison to a broader-gauge network, and the surplus equipment generates no cash flow during periods of low demand. In regions where narrow-gauge lines form a small part of the rail network (as was the case on Russia's Sakhalin Railway), extra cost is involved in designing, manufacturing or importing narrow-gauge equipment.
Solutions to interchangeability problems include , a rollbock system, dual gauge, variable gauge, or gauge conversion.
Lines for iron ore to Kribi in Cameroon are likely to be with a likely connection to the same port from the Cameroon system.
Nigeria's railways are mostly Cape gauge. The Lagos–Kano Standard Gauge Railway is a gauge conversion project by the Nigerian Government to create a north–south standard gauge rail link. The first converted segment, between Abuja and Kaduna, was completed in July 2016.
The African Union has a 50-year plan to connect the capital cities and major centres by high-speed railways.
"Standard" gauge appears
Gauge differences
Gauge selection in other countries
Terminology
Standard gauge
Broad gauge
Medium gauge
Narrow gauge
Minimum gauge
Break of gauge
Dual gauge
In November 1871 a novelty in the shape of a mixed-gauge goods train was introduced between Truro and Penzance. It was worked by a narrow-gauge engine, and behind the narrow-gauge trucks came a broad-gauge match-truck with wide buffers and sliding shackles, followed by the broad-gauge trucks. Such trains continued to run in West Cornwall until the abolition of the Broad Gauge; they had to stop or come down to walking pace at all stations where fixed points existed and the narrow portion side-stepped to right or left.
Triple gauge
Nominal track gauge
Units
Imperial foot Castilian foot Portuguese foot 5 Portuguese feet = Swedish foot Prussian foot (Rheinfuß) Prussian feet = Austrian fathom Austrian fathom =
Temporary way – permanent way
Maintenance standards
Advantages and disadvantages of different track gauges
Construction cost
Interchangeability
Dominant railway gauges
Metre-gauge railway 7.2% Argentina (), Brazil (), Bolivia, northern Chile, Greece (in the disused Peloponnese network), Spain (Renfe Feve, FGC, Euskotren Trena, FGV, SFM), Switzerland (Rhaetian Railway, MOB, BOB, MGB), Malaysia, Thailand, Cambodia, Bangladesh, East Africa, Vietnam 3 ft 6 in gauge railways 8.5% Southern and Central Africa; Nigeria (most); Indonesia (Java and Sumatera) ; Japan; Taiwan; Philippines; New Zealand; and the Australian states of Queensland, Western Australia, Tasmania and South Australia. 54.9% Albania, Argentina, Australia, Austria, Belgium, Bosnia and Herzegovina, Brazil (), Bulgaria, Canada, China, Croatia, Cuba, Czech Republic, Denmark, Djibouti, DR Congo (Kamina-Lubumbashi section, planned), Ethiopia, France, Germany, Great Britain (United Kingdom), Greece, Hong Kong, Hungary, India (only used in rapid transit and High-speed rail), Indonesia (Aceh, LRT Jabodetabek, LRT Jakarta, MRT Jakarta East - West Line Corridor, High-speed rail in Indonesia, and Sulawesi), Italy, Israel, Kenya (Mombasa–Nairobi Standard Gauge Railway), Laos, Liechtenstein, Lithuania (Rail Baltica), Luxembourg, Macedonia, Mauritius (Metro Express), Mexico, Montenegro, Netherlands, North Korea, Norway, Panama, Peru, Philippines, Poland, Romania, Serbia, Singapore MRT, Slovakia, Slovenia, South Korea, Spain (AVE, Alvia and FGC), Sweden, Switzerland, Turkey, United States, Uruguay, Venezuela, north Vietnam. Also private companies' lines and JR high-speed lines in Japan. High-speed lines in Taiwan. Gautrain commuter system in South Africa. New lines in Tanzania and Nigeria. 5 ft and 1520 mm gauge railways 16.8% Armenia, Azerbaijan, Belarus, Georgia, Kazakhstan, Kyrgyzstan, Latvia, Lithuania, Moldova, Mongolia, Russia, Tajikistan, Turkmenistan, Ukraine, Uzbekistan.
(all contiguous – redefined from ) 0.5% Estonia, Estonian railways today , p. 32 Finland
(contiguous, and generally compatible, except high speed trains, with 5 ft 3 in gauge railways 0.7% Ireland, Northern Ireland (United Kingdom) (), and in the Australian states of Victoria and South Australia (), Brazil () Iberian-gauge railways 1.2% Portugal, Spain. Sometimes referred to as Iberian gauge. In Spain the Administrador de Infraestructuras Ferroviarias (ADIF) managed of this gauge and of mixed gauge at end of 2010.Karl Arne Richter (editor), Europäische Bahnen '11, Eurailpress, Hamburg, 2010, The Portuguese Rede Ferroviária Nacional (REFER) managed of this gauge of this track at the same date. 5 ft 6 in gauge railways 10.2% India, Pakistan, Bangladesh, Sri Lanka, Argentina, Chile, BART in the United States San Francisco Bay Area
Prevalence
Narrow gauge(s) 17.5% 15.8% Standard gauge 60.6% 54.9% Broad gauge(s) 21.8% 29.3% Totals 100% 100%
Future
Europe
Trans-Asian Railway
The Americas
Africa
Timeline
George Stephenson Horatio Allen for the South Carolina Canal and Rail Road Company Henry Archer for the Festiniog Railway to easily navigate mountainous terrain
(Britain's first steam-hauled narrow gauge passenger service in 1865) (originally horse-drawn)I. K. Brunel George Washington Whistler for the Moscow – Saint Petersburg Railway based on Southern US practice Chosen in Ireland as a compromise Lord Dalhousie for British India, following recommendations of Mr. W. Simms, a consulting engineer Carl Pihl for the Røros Line in Norway to reduce costs Abraham Fitzgibbon for the Queensland Railways to reduce costs William Jackson Palmer for the Denver & Rio Grande Railway to reduce costs (inspired by the Festiniog Railway) George E. Mansfield for the Billerica and Bedford Railroad to reduce costs (inspired by the Festiniog Railway) Everard Calthrop to reduce costs; had designs for a matching fleet of rolling stock
See also
Notes
External links
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