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Gauge conversion is the changing of one railway track gauge (the distance between the running rails) to another.
If tracks are converted to a narrower gauge, the existing sleepers (ties) may be used. However, replacement is required if the conversion is to a significantly wider gauge. Some sleepers may be long enough to accommodate the fittings of both existing and alternative gauges. Wooden sleepers are suitable for conversion because they can be drilled for the repositioned rail spikes. Being difficult to drill, concrete sleepers are less suitable for conversion. Concrete sleepers may be cast with alternative gauge fittings in place, an example being those used during the conversion of the Melbourne–Adelaide railway from 1600 mm (5 ft 3 in) to 1435 mm (4 ft 8+1⁄2 in). Steel sleepers may have alternative gauge fittings cast at production, may be drilled for new fittings or may be welded with new fittings.
Conversion from a narrow to a wider gauge may require enlargement of the structure gauge of the bridges, overpasses and tunnels, embankments and cuts. The minimum curve radius may have a larger radius on broader gauges requiring route deviations to allow the minimum curve radius to be increased. Track centers at stations with multiple tracks may also have to be increased. Conversion from narrow to standard gauge can cause several changes not because of the gauge itself, but in order to be compatible with the structure gauge of standard gauge track, such as height of overpasses so that trains can be exchanged. The choice of train couplers may be a factor as well.
Where vehicles move to a different gauge, they must either be prepared for bogie exchange or be prepared for wheelset exchange. For example, passenger trains moving between the 1435 mm (4 ft 8+1⁄2 in) in France and the 1668 mm (5 ft 5+21⁄32 in) gauge in Spain pass through an installation which adjusts their variable-gauge axles. This process is known as "gauge change". Goods wagons are still subject to either bogie exchange or wheelset exchange.
Some steam locomotives were constructed to be reconfigured to a different gauge: for example, some East African Railways locomotives; Garratts; the large 500, 600 and 700 class locomotives of the South Australian Railways introduced by William Webb in 1926; [1] and the Victorian Railways J, N and R classes. In the Australian instances, conversion was anticipated from 1600 mm (5 ft 3 in) broad gauge to 1435 mm (4 ft 8+1⁄2 in) standard gauge. Conversion to a wider gauge was similarly anticipated for the large 1067 mm (3 ft 6 in) narrow-gauge Western Australian Government Railways V class locomotive (to standard gauge). [2] Of these locomotives, only one R class was converted (when in preservation). [3] Two unanticipated conversions to occur were the ten locomotives of the South Australian Railways 740 class (from standard to broad gauge) and five 1067 mm (3 ft 6 in) narrow-gauge T class locomotives, which became the Tx class on the broad gauge before they were eventually converted back again. [4]
Gauge-change in steam locomotives has a long lineage. In about 1860, the Bristol and Exeter Railway converted five 1435 mm (4 ft 8+1⁄2 in) locomotives to 7 ft 1⁄4 in (2140 mm) gauge, and later converted them back again. Also in the 19th century, in the United States, some 5 ft (1524 mm) broad-gauge locomotives were designed for easy conversion to 1,435 mm (4 ft 8+1⁄2 in) gauge, and in the United Kingdom some 7 ft 1⁄4 in (2140 mm) broad-gauge locomotive classes of the Great Western Railway were designed for easy conversion to 1435 mm (4 ft 8+1⁄2 in) gauge. [5] After World War II, a number of captured German 03 class Pacifics locomotives were re-gauged to the 5 ft (1524 mm) Russian gauge.
Most diesel and electric rolling stock can undergo gauge conversion by replacement of their bogies. Engines with fixed wheelbases are more difficult to convert. In Australia, diesel locomotives are regularly re-gauged between broad, standard and narrow gauges.
Gauge conversion of wagons and coaches involves the replacement of the wheelsets or the bogies. In May 1892, wagons and coaches were converted when the 7 ft 1⁄4 in (2140 mm) gauge of the Great Western Railway was abandoned.
During or after gauge conversion work, some stations and branch lines may become "gauge orphans". This occurs especially when it is not considered economically worthwhile to go to the expense of gauge conversion. For example, on the standard gauge line between Adelaide and Melbourne, the broad gauge Victor Harbor branch line became a gauge orphan after the main line was converted in 1995 because it was too lightly trafficked; it now prospers as a heritage line, SteamRanger.
A narrow-gauge railway is a railway with a track gauge narrower than standard 1,435 mm. 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.
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.
In railway engineering, "gauge" is the transverse distance between the inner surfaces of the heads of two rails, which for the vast majority of railway lines is the number of rails in place. However, it is sometimes necessary for track to carry railway vehicles with wheels matched to two different gauges. Such track is described as dual gauge – achieved either by addition of a third rail, if it will fit, or by two additional rails. Dual-gauge tracks are more expensive to configure with signals and sidings, and to maintain, than two separate single-gauge tracks. It is therefore usual to build dual-gauge or other multi-gauge tracks only when necessitated by lack of space or when tracks of two different gauges meet in marshalling yards or passenger stations. Dual-gauge tracks are by far the most common configuration, but triple-gauge tracks have been built in some situations.
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 Amerton Railway is a 2 ft narrow gauge heritage railway in the English county of Staffordshire. It is owned by Staffordshire Narrow Gauge Railway Limited, a registered charity, and operated by volunteers.
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.
A variable gauge system allows railway vehicles in a train to travel across a break of gauge between two railway networks with different track gauges. For through operation, a train must be equipped with special bogies holding variable gauge wheelsets which contain a variable gauge axle (VGA).
South Australian Railways (SAR) was the statutory corporation through which the Government of South Australia built and operated railways in South Australia from 1854 until March 1978, when its non-urban railways were incorporated into Australian National, and its Adelaide urban lines were transferred to the State Transport Authority.
The rail network in Queensland, Australia, was the first in the world to adopt 1,067 mm narrow gauge for a main line, and now the second largest narrow gauge network in the world, consists of:
Rollbocks, sometimes called transporter trailers, are narrow gauge railway trucks or bogies that allow a standard gauge wagon to 'piggyback' on a narrow-gauge line. The Vevey system enables a coupled train of standard gauge wagons to be automatically loaded or rolled onto Rollbocks, so that the train can then continue through a change of gauge.
In railroad industry, the Ramsey car-transfer apparatus was a device to replace bogies on railroad cars to permit transfer of a train between railroad lines with different gauge.
Rail transport in Australia involves a number of narrow-gauge railways. In some states they formed the core statewide network, but in the others they were either a few government branch lines, or privately owned and operated branch lines, often for mining, logging or industrial use.
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.
The N Class are a class of diesel locomotives built by Clyde Engineering, Somerton for V/Line between 1985 and 1987.
5 ft 6 in / 1,676 mm is a broad track gauge, used in India, Pakistan, western Bangladesh, Sri Lanka, Argentina, Chile, and on BART in the San Francisco Bay Area.
Indian-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.
The DB Class V 51 and DB Class V 52 are classes of almost identical narrow gauge 4 axle diesel hydraulic locomotives built in 1964 for the Deutsche Bundesbahn, being built for 750 mm and 1,000 mm gauge lines respectively.
The 700 class is a class of six diesel-electric locomotives based on the Alco DL500G model, built by AE Goodwin, Auburn, New South Wales for the South Australian Railways. They are virtually identical to the New South Wales 442 class locomotive.
