A narrow-gauge railway is a railway with a track gauge narrower than 1,435 mmstandard gauge. Most narrow-gauge railways are between 600 mm and 1,067 mm.
A standard-gauge railway is a railway with a track gauge of 1,435 mm. The standard gauge is also called Stephenson gauge, international gauge, UIC gauge, uniform gauge, normal gauge and European 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.
A broad-gauge railway is a railway with a track gauge broader than the 1,435 mm used by standard-gauge railways.
The Great Western Railway (GWR) was a British railway company that linked London with the southwest, west and West Midlands of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament on 31 August 1835 and ran its first trains in 1838 with the initial route completed between London and Bristol in 1841. It was engineered by Isambard Kingdom Brunel, who chose a broad gauge of 7 ft —later slightly widened to 7 ft 1⁄4 in —but, from 1854, a series of amalgamations saw it also operate 4 ft 8+1⁄2 in standard-gauge trains; the last broad-gauge services were operated in 1892.
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.
With railways, a break of gauge occurs where a line of one track gauge meets a line of a different gauge. Trains and rolling stock generally cannot run through without some form of conversion between gauges, leading to passengers having to change trains and freight requiring transloading or transshipping; this can add delays, costs, and inconvenience to travel on such a route.
The Bristol and Gloucester Railway was a railway company opened in 1844 to run services between Bristol and Gloucester. It was built on the 7 ftBrunel gauge, but it was acquired in 1845 by the 4 ft 8+1⁄2 instandard gauge Midland Railway, which also acquired the Birmingham and Gloucester Railway at the same time.
Railways with a railway track gauge of 5 ft first appeared in the United Kingdom and the United States. This gauge became commonly known as "Russian gauge", because the government of the Russian Empire chose it in 1843. Former areas and states of the Empire have inherited this standard. However in 1970, Soviet Railways re-defined the gauge as 1,520 mm.
Rail gauges in Australia display significant variations, which has presented an extremely difficult problem for rail transport on the Australian continent since the 19th century. As of 2022, there are 11,914 kilometres (7,403 mi) of narrow-gauge railways, 18,007 kilometres (11,189 mi) of standard gauge railways and 2,685 kilometres (1,668 mi) of broad gauge railways. In the 19th century, each of the colonies of Australia adopted their own gauges.
The history of rail transport in Great Britain 1830–1922 covers the period between the opening of the Liverpool and Manchester Railway (L&MR), and the Grouping, the amalgamation of almost all of Britain's many railway companies into the Big Four by the Railways Act 1921.
The 4 ft 6 in track gauge, also called the Scotch gauge, was adopted by early 19th century railways mainly in the Lanarkshire area of Scotland. It differed from the gauge of 4 ft 8 in that was used on some early lines in England. Early railways chose their own gauge, but later in the century interchange of equipment was facilitated by establishing a uniform rail gauge across railways: the 'standard gauge' of 4 ft 8+1⁄2 in. In the early 1840s standard gauge lines began to be constructed in Scotland, and all the Scotch gauge lines were eventually converted to standard gauge. The building of new Scotch gauge railways was outlawed in Great Britain in 1846 by the Regulating the Gauge of Railways Act 1846. From 1903, tram lines of Tokyo adopted this gauge.
Bogie exchange is a system for operating railway wagons on two or more gauges to overcome difference in the track gauge. To perform a bogie exchange, a car is converted from one gauge to another by removing the bogies or trucks, and installing a new bogie with differently spaced wheels. It is generally limited to wagons and carriages, though the bogies on diesel locomotives can be exchanged if enough time is available.
Gauge conversion is the changing of one railway track gauge to another.
The track gauge adopted by the mainline railways in Ireland is 1,600 mm. This unusually broad track gauge is otherwise found only in Australia, in the states of Victoria, southern New South Wales and South Australia, as well as in Brazil.
Railways with a track gauge of 5 ft 3 in fall within the category of broad gauge railways. As of 2022, they were extant in Australia, Brazil and Ireland.
Iberian gauge is a track gauge of 1,668 mm, most extensively used by the railways of Spain and Portugal. This is the second-widest gauge in regular use anywhere in the world. Indian gauge railways, 5 ft 6 in, are 8 mm wider.
Track gauge in Canada is standard gauge of 4 ft 8+1⁄2 in, except for Toronto transit systems and the White Pass and Yukon Route. Rail lines built during the 19th century with a broad gauge of 5 ft 6 in were converted to standard gauge.
Baulk road is the name given to a type of railway track or 'rail road' that is formed using rails carried on continuous timber bearings, as opposed to the more familiar 'cross-sleeper' track that uses closely spaced sleepers or ties to give intermittent support to stronger rails.
The United Kingdom Royal Commission on Railway Gauges was held in 1845 to choose between the 7 ft broad gauge of the Great Western Railway and its associated companies and the so-called narrow gauge of 4 ft 8+1⁄2 in that had been installed in most of the rest of the country. The situation in Ireland, where there were three gauges, was also considered.
