Gauge conversion is the changing of one railway
track gauge (the distance between the running rails) to another.
Sleepers
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 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 to . Steel sleepers may have alternative gauge fittings cast at production, may be drilled for new fittings or may be welded with new fittings.
Structures
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
In classical geometry, a radius ( : radii) of a circle or sphere is any of the line segments from its center to its perimeter, and in more modern usage, it is also their length. The name comes from the latin ''radius'', meaning ray but also the ...
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.
Rail vehicles
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 in France and the 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
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 (the chassis cont ...
.
Steam locomotives
Some
steam locomotives were constructed to be reconfigured to a different gauge: for example, some
East African Railways
The East African Railways and Harbours Corporation (EAR&H) is a defunct company that operated railways and harbours in East Africa from 1948 to 1977. It was formed in 1948 for the new East African High Commission by merging the Kenya and Ugand ...
locomotives;
Garratts; the large
500 500 may refer to:
* 500 (number)
* 500 BC
* AD 500
Buildings and places
* 500 Boylston Street of Boston
* 500 Brickell in Miami
* 500 Capitol Mall in Sacramento
* 500 Fifth Avenue
* 500 Renaissance Center, one of seven buildings in the GM Renai ...
,
600 and
700 class locomotives of the
South Australian Railways introduced by
William Webb in 1926;
[ and the Victorian Railways J, N and R classes. In the Australian instances, conversion was anticipated from broad gauge to standard gauge. Conversion to a wider gauge was similarly anticipated for the large narrow-gauge Western Australian Government Railways V class locomotive (to standard gauge). Of these locomotives, only one R class was converted (when in preservation). Two unanticipated conversions to occur were the ten locomotives of the South Australian Railways 740 class (from standard to broad gauge) and five narrow-gauge T class locomotives, which became the Tx class on the broad gauge before they were eventually converted back again.]
Gauge-change in steam locomotives has a long lineage. In about 1860, the Bristol and Exeter Railway converted five locomotives to gauge, and later converted them back again. Also in the 19th century, in the United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., federal district, five ma ...
, some broad-gauge locomotives were designed for easy conversion to gauge. In the 20th century, in Victoria station, London
Victoria station, also known as London Victoria, is a central London railway terminus and connected London Underground station in Victoria, in the City of Westminster, managed by Network Rail. Named after the nearby Victoria Street (not the ...
, some broad-gauge locomotive classes of the Great Western Railway
The Great Western Railway (GWR) was a British railway company that linked London
London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 mill ...
were designed for easy conversion to gauge. After World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...
, a number of captured German 03 class Pacifics locomotives were re-gauged to the Russian gauge.
Diesel and electric locomotives and trains
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.
Wagons and coaches
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 gauge of the Great Western Railway
The Great Western Railway (GWR) was a British railway company that linked London
London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 mill ...
was abandoned.
Gauge orphan
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.
See also
Rail transport
* List of gauge conversions
* Break-of-gauge
* Dual gauge
Notes
References
{{DEFAULTSORT:Gauge Conversion
Track gauges