Quadruple track
Encyclopedia
Quadruple track railway consists of four parallel tracks. On a quad-track line, two tracks are used in each direction. It is also sometimes called four-track railway.
Some tracks are only triplicated, having only one extra track to relieve congestions, while some tracks are sextuplicated, i.e., three pairs of tracks with three tracks on each direction.
A faster express line and a stopping local line are separated, with each having a separate pair of tracks.
Construction of new double tracks dedicated to high-speed rail
alongside existing conventional double track used by regional and local passenger trains and freight trains is a form of quadruple track. It increases the capacity of that route significantly, and allows for significant increases in inter-city high-speed train frequency with reduced travel times.
Long distance inter-city rail
and freight trains are separated from short distance commuter rail. This helps to prevent delays on one service affecting the other, and is commonly seen in metropolitan areas. Quadruplication may be necessary when a new commuter rail service begins to operate on an existing line. Sometimes the local trains have separate technology, such as electrical system or signalling, which requires strict separation, for example in Berlin or Copenhagen.
When a quadruple track line divides to different destinations part way along, trains need to be sorted by their destination.
Passenger trains and freight trains can be separated with each different track.
A variation of this can be found on the quadruple track section of the Main North railway line
in New South Wales
between Waratah
and Maitland
where one pair of tracks are used exclusively for coal trains and the other pair are used for passenger trains and general freight. A similar process, but with all intercity and commuter passenger trains on the outer tracks and thru-freight trains on the inner tracks, was done by the Pennsylvania Railroad
on its New York-Washington and Philadelphia-Pittsburgh mainlines prior to the takeover of operations by Amtrak
and Conrail (and later Norfolk Southern). This is somewhat still done to this day by NS, CSX, and Conrail Shared Assets trains on Amtrak-owned trackage in the Philadelphia area.
Two double track lines along opposite sides of a river can operate as a quadruple track. Examples of this can be found in Rhone
in France and Rhine in Germany.
Some tracks are only triplicated, having only one extra track to relieve congestions, while some tracks are sextuplicated, i.e., three pairs of tracks with three tracks on each direction.
Advantages of quadruple track
- Quadruple track can manage a larger amount of traffic with usually twice the capacity of double track. It is often seen around large metropolisMetropolisA metropolis is a very large city or urban area which is a significant economic, political and cultural center for a country or region, and an important hub for regional or international connections and communications...
or on busy inter-city corridors. - In quadruple track, faster trains can overtake slower ones, and quadrupling can contribute to faster operation of trains. High-speed railHigh-speed railHigh-speed rail is a type of passenger rail transport that operates significantly faster than the normal speed of rail traffic. Specific definitions by the European Union include for upgraded track and or faster for new track, whilst in the United States, the U.S...
of 200 km/h average speed and commuter rail of 40 km/h average can co-exist in quadruple track without interrupting each other. - It is relatively easy to do maintenance and engineering work of tracks in quadruple line with minimum effect of train delay because double-track service is kept even if the other two double tracks are halted during the work.
Disadvantages of quadruple track
- Quadruple track costs more due to requiring more materials and increased land acquisition costs. This also applies to tunneling and bridge costs.
- When adding tracks, land acquisition can become prohibitively expensive.
- Maintenance costs are higher and often more complex as there may be more switches on the track than on a two-track line (to facilitate switching from outer to inner tracks and vice versa).
- For safety reasons, grade separations are almost always required.
Quadruple track operation
In quadruple track, trains are sorted in various ways in order to make maximum use of track capacity. These can include one or a combination of:- Sorting by speed
A faster express line and a stopping local line are separated, with each having a separate pair of tracks.
Construction of new double tracks dedicated to high-speed rail
High-speed rail
High-speed rail is a type of passenger rail transport that operates significantly faster than the normal speed of rail traffic. Specific definitions by the European Union include for upgraded track and or faster for new track, whilst in the United States, the U.S...
alongside existing conventional double track used by regional and local passenger trains and freight trains is a form of quadruple track. It increases the capacity of that route significantly, and allows for significant increases in inter-city high-speed train frequency with reduced travel times.
- Sorting by distance
Long distance inter-city rail
Inter-city rail
Inter-city rail services are express passenger train services that cover longer distances than commuter or regional trains.There is no precise definition of inter-city rail. Its meaning may vary from country to country...
and freight trains are separated from short distance commuter rail. This helps to prevent delays on one service affecting the other, and is commonly seen in metropolitan areas. Quadruplication may be necessary when a new commuter rail service begins to operate on an existing line. Sometimes the local trains have separate technology, such as electrical system or signalling, which requires strict separation, for example in Berlin or Copenhagen.
- Sorting by destination
When a quadruple track line divides to different destinations part way along, trains need to be sorted by their destination.
- Sorting by passenger/ freight
Passenger trains and freight trains can be separated with each different track.
A variation of this can be found on the quadruple track section of the Main North railway line
Main North railway line, New South Wales
The Main North Line is a major railway in New South Wales, Australia. It runs through the Central Coast, Hunter and the New England regions. The line was the original main line between Sydney and Brisbane, however this required a change of gauge at Wallangarra...
in New South Wales
New South Wales
New South Wales is a state of :Australia, located in the east of the country. It is bordered by Queensland, Victoria and South Australia to the north, south and west respectively. To the east, the state is bordered by the Tasman Sea, which forms part of the Pacific Ocean. New South Wales...
between Waratah
Waratah, New South Wales
Waratah is a north-western residential suburb of Newcastle, New South Wales, Australia, located from Newcastle's central business district and bounded on the north by the Main North line. Waratah station was opened in 1858 and is served by CityRail's Hunter line.- History :Waratah was once a major...
and Maitland
Maitland, New South Wales
Maitland is a city in the Lower Hunter Valley of New South Wales, Australia and the seat of Maitland City Council, situated on the Hunter River approximately by road north of Sydney and north-west of Newcastle...
where one pair of tracks are used exclusively for coal trains and the other pair are used for passenger trains and general freight. A similar process, but with all intercity and commuter passenger trains on the outer tracks and thru-freight trains on the inner tracks, was done by the Pennsylvania Railroad
Pennsylvania Railroad
The Pennsylvania Railroad was an American Class I railroad, founded in 1846. Commonly referred to as the "Pennsy", the PRR was headquartered in Philadelphia, Pennsylvania....
on its New York-Washington and Philadelphia-Pittsburgh mainlines prior to the takeover of operations by Amtrak
Amtrak
The National Railroad Passenger Corporation, doing business as Amtrak , is a government-owned corporation that was organized on May 1, 1971, to provide intercity passenger train service in the United States. "Amtrak" is a portmanteau of the words "America" and "track". It is headquartered at Union...
and Conrail (and later Norfolk Southern). This is somewhat still done to this day by NS, CSX, and Conrail Shared Assets trains on Amtrak-owned trackage in the Philadelphia area.
- Other modes
Two double track lines along opposite sides of a river can operate as a quadruple track. Examples of this can be found in Rhone
Rhône
Rhone can refer to:* Rhone, one of the major rivers of Europe, running through Switzerland and France* Rhône Glacier, the source of the Rhone River and one of the primary contributors to Lake Geneva in the far eastern end of the canton of Valais in Switzerland...
in France and Rhine in Germany.
Examples
America
- The New York Central RailroadNew York Central RailroadThe New York Central Railroad , known simply as the New York Central in its publicity, was a railroad operating in the Northeastern United States...
's Water Level Route was the first long distance 4-track railroad in the world. - Much of AmtrakAmtrakThe National Railroad Passenger Corporation, doing business as Amtrak , is a government-owned corporation that was organized on May 1, 1971, to provide intercity passenger train service in the United States. "Amtrak" is a portmanteau of the words "America" and "track". It is headquartered at Union...
's Northeast CorridorNortheast CorridorThe Northeast Corridor is a fully electrified railway line owned primarily by Amtrak serving the Northeast megalopolis of the United States from Boston in the north, via New York to Washington, D.C. in the south, with branches serving other cities...
from WashingtonWashington, D.C.Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....
to New Haven is a four track line. - The Pennsylvania RailroadPennsylvania RailroadThe Pennsylvania Railroad was an American Class I railroad, founded in 1846. Commonly referred to as the "Pennsy", the PRR was headquartered in Philadelphia, Pennsylvania....
had a four-track mainline carrying freight from Pittsburgh to Harrisburg via the Horseshoe Curve. This was how the name Broadway LimitedBroadway LimitedThe Broadway Limited was the Pennsylvania Railroad's premier named passenger train, operating daily in each direction between New York City and Chicago, via North Philadelphia. It replaced its predecessors, the Pennsylvania Limited and the Pennsylvania Special...
came about due the "Broadway of a 4 track main." - The BNSF RacetrackBNSF Railway LineThe BNSF Railway Line is a commuter rail line in the United States, provided by Metra and operated by the BNSF Railway in Chicago and its surrounding suburbs...
in ChicagoChicagoChicago is the largest city in the US state of Illinois. With nearly 2.7 million residents, it is the most populous city in the Midwestern United States and the third most populous in the US, after New York City and Los Angeles...
has a quadruple track section from Union Station to Lavergne. - New York City SubwayNew York City SubwayThe New York City Subway is a rapid transit system owned by the City of New York and leased to the New York City Transit Authority, a subsidiary agency of the Metropolitan Transportation Authority and also known as MTA New York City Transit...
- many lines of the New York CityNew York CityNew York is the most populous city in the United States and the center of the New York Metropolitan Area, one of the most populous metropolitan areas in the world. New York exerts a significant impact upon global commerce, finance, media, art, fashion, research, technology, education, and...
Subway are quadrupled. Hence, many express services are operated in the New York City Subway. Express trains and local trains are separated with each different track.
Europe
- Significant lengths of the West CoastWest Coast Main LineThe West Coast Main Line is the busiest mixed-traffic railway route in Britain, being the country's most important rail backbone in terms of population served. Fast, long-distance inter-city passenger services are provided between London, the West Midlands, the North West, North Wales and the...
, Great WesternGreat Western Main LineThe Great Western Main Line is a main line railway in Great Britain that runs westwards from London Paddington station to the west of England and South Wales. The core Great Western Main Line runs from London Paddington to Temple Meads railway station in Bristol. A major branch of the Great...
and East Coast Main LineEast Coast Main LineThe East Coast Main Line is a long electrified high-speed railway link between London, Peterborough, Doncaster, Wakefield, Leeds, York, Darlington, Newcastle and Edinburgh...
s in Great BritainRail transport in Great BritainThe railway system in Great Britain is the oldest in the world, with the world's first locomotive-hauled public railway opening in 1825. As of 2010, it consists of of standard gauge lines , of which are electrified. These lines range from single to double, triple, quadruple track and up to twelve...
are quadruple track, with the remainder of the lines being double track. These lines are high capacity and high speed lines running from GlasgowGlasgowGlasgow is the largest city in Scotland and third most populous in the United Kingdom. The city is situated on the River Clyde in the country's west central lowlands...
, BristolBristolBristol is a city, unitary authority area and ceremonial county in South West England, with an estimated population of 433,100 for the unitary authority in 2009, and a surrounding Larger Urban Zone with an estimated 1,070,000 residents in 2007...
and EdinburghEdinburghEdinburgh is the capital city of Scotland, the second largest city in Scotland, and the eighth most populous in the United Kingdom. The City of Edinburgh Council governs one of Scotland's 32 local government council areas. The council area includes urban Edinburgh and a rural area...
to LondonLondonLondon is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
. - The London Waterloo to SouthamptonSouthamptonSouthampton is the largest city in the county of Hampshire on the south coast of England, and is situated south-west of London and north-west of Portsmouth. Southampton is a major port and the closest city to the New Forest...
/ SalisburySalisburySalisbury is a cathedral city in Wiltshire, England and the only city in the county. It is the second largest settlement in the county...
main line South Western Main LineSouth Western Main LineThe South Western Main Line is a railway line between London Waterloo and Weymouth on the Dorset coast, in the south of England. It is a major railway which serves many important commuter areas, as well as the major settlements of Southampton and Bournemouth...
from London Waterloo to Worting JunctionWorting JunctionWorting Junction is a railway junction on the former LSWR route south of Basingstoke where the line divides to go towards Salisbury or Southampton.-History:...
, Great Britain. - The Berlin Stadtbahn, Germany, has four tracks.
- The İstanbul-Ankara Main LineIstanbul-Ankara Main LineThe İstanbul-Ankara Main Line is the busiest rail line in Turkey, in terms of railway and passenger traffic and is the primary route of the State Railways as it serves a large population between Turkey's two largest cities. The line is long and runs between Turkey's largest city İstanbul to...
has a quadruple track section between Etimesgut and Kızılay in AnkaraAnkaraAnkara is the capital of Turkey and the country's second largest city after Istanbul. The city has a mean elevation of , and as of 2010 the metropolitan area in the entire Ankara Province had a population of 4.4 million....
, TurkeyTurkeyTurkey , known officially as the Republic of Turkey , is a Eurasian country located in Western Asia and in East Thrace in Southeastern Europe...
.
Asia
- The Tung Chung Line and the Airport ExpressAirport ExpressAirport Express can refer to the following:*AirPort Express, a wireless product by Apple Inc.*Several airport rail links are named Airport Express:**Airport Express , the airport transit service in Beijing, China...
in Hong Kong are quadruplicated between Kowloon and Tsing Yi stations, but share two tracks on the rest of their routes (until they diverge before the western end). The two lines shared two tracks when they were opened in 1998. - The Gyeongbu LineGyeongbu LineThe Gyeongbu Line is the most important railway line in South Korea and one of the oldest. It was constructed by Japan in 1905, connecting Seoul to Suwon, Daejeon, Daegu, and Busan. The Gyeongbu Line is by far the most heavily travelled rail line in South Korea...
in South Korea is quadruplicated on 84.9km on its route, and sextuplicated on a further 11.7km