Quadruple track

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Four track section of the East Coast Main Line, UK.

A quadruple-track railway (also known as a four-track railway) is a railway line consisting of four parallel tracks, with two tracks used in each direction. Quadruple-track railways can handle large amounts of traffic, and so are used on very busy routes.

Some tracks are only tripled, having only one extra track to relieve congestion, while some tracks are sextupled, i.e., six parallel tracks with three tracks in each direction.

Advantages of quadruple track[edit]

  • Quadruple track can manage a larger amount of traffic with usually twice the capacity of double track. It is often seen around large metropolis 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 rail 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[edit]

  • 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 (points) on the track than on a two-track line (to facilitate switching from outer to inner tracks and vice versa).
  • For safety, costly grade separations are almost always required.
  • If needing more capacity, it can be better to add a double track along a different route, because it could improve local and regional transit much along an under-served route, and reduce land acquisition cost by choosing a less built-up area.

Quadruple-track operation[edit]

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 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 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. Quadrupling 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 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.

  • 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 in France and Rhine in Germany.

Quadruple-track layouts[edit]

As it can be seen from the pictures below in the Gallery of diagrams, the four tracks can be paired either by direction (slow/fast in each pair) or by purpose (speed or direction in each pair). Sometimes two of the tracks go more straight and with a little distance from the two other. This is a design decision when widening a double track section, and allows higher speed on the faster tracks.

4-track section of Amtrak's Northeast Corridor in New Jersey


The Americas[edit]

Quadruple track section of the West Coast Main Line in Great Britain




Huning Lines

(All high-speed new lines that have different stations don't qualify here)

  • The Guangzhou–Shenzhen Railway is quadruplicated in 2007 for its entire length separating passenger (upgraded high-speed) with freight (and conventional passenger) traffic. It is the first railway in China to do so. (The third track was added in 2000, when conventional track use only 1 track and have to run at high-speed track at some times, causing disruption in schedules, so the fourth track is built.)
    • The Beijing-Guangzhou-Shenzhen-Hong Kong High-speed railway have different routes and stations.
  • The Shanghai–Nanjing Intercity Railway runs parallel to the slower conventional Nanjing-Shanghai Railway and share many stations for most of its length, effectively making it a 4-track corridor a majority of its length.
    • The Beijing-Shanghai High-speed railway have different routes and (with a few exceptions) stations.
  • The Jiaozhou-Jinan Passenger-Dominated Line runs parallel to the slower conventional Jiaozhou-Jinan Railway and share many stations for most of its length, and are formally called JiaoJi (Passenger-Dominated) Line when describing train routes, effectively treating JiaoJi line as quadruple track.
    • The Jiaozhou-Jinan High-speed railway (not to be confused with the above) is in long-term planning and have different routes and (with a few exceptions) stations.
  • Beijing-Kowloon Railway (Nanchang-Jiujiang section) / Nanchang-Jiujiang Intercity Railway. Conventional long-distance trains run on both, and the two lines share all its stations.
  • Hunan-Guangxi Railway (Hengyang-Liuzhou section)

Hong Kong[edit]

  • The Tung Chung Line and the Airport Express in Hong Kong are quadruplicated between Kowloon and Tsing Yi stations since 2003, but share two tracks on the rest of their routes (until they diverge again before the western end). The two lines shared two tracks when they were opened in 1998 with separate platforms at stations. In addition, the West Rail runs largely parallel to the Tung Chung Line and the Airport Express throughout Kowloon and New Kowloon, meaning six tracks running side-by-side.
  • The Ocean Park Cable Car system has two pairs of ropeways.



Four track stretch of the Keihan Main Line in Japan
  • Hankyu Railway in Osaka has a sextuplicated section between Umeda and Juso stations (2.4 km).[4]
  • Keihan Main Line in Osaka is quadruplicated between Temmabashi and Neyagawa Signal Box (~13 km).[5]
  • Seibu Ikebukuro Line in Tokyo is quadruplicated between Nerima to Nerima-Takanodai stations (3.5 km).
  • Between Tokyo and Odawara (JR East) 83.9 km is paired by use (not including Shinkansen).[6]
    • Tokyo – Shinagawa 6.8 km: 6 tracks (8 if include Sobu-Yokosuka Line Underground)
    • Shinagawa – Tsurumi 14.9 km: 4 tracks
    • Tsurumi – Yokohama 7.1 km: 6 tracks
    • Yokohama – Totsuka 12.1 km: 4 tracks
    • Totsuka – Ofuna 5.6 km: 6 tracks
    • Ofuna – Odawara 37.4 km: 4 tracks
  • Between Tokyo and Omiya (JR East) is paired by use (not including Shinkansen)[7]
    • Tokyo – Akihabara: 6 tracks
    • Akihabara – Ueno: 6 tracks
      • (Tokyo – Ueno 3.6 km)
    • Ueno – Nippori 2.2 km: 10 tracks (2 for Ueno Depot)
    • Nippori – Tabata: 4 tracks
    • Nippori – Oku: 4 tracks
    • Tabata – Akabane: 4 tracks
    • Oku – Akabane: 2 tracks
      • (Nippori – Akabane 7.4 km)
    • Akabane – Omiya 17.1 km: 6 tracks
  • Between Kusatsu and Nishi-Akashi (JR West) 120.9 km (not including Shinkansen)[8]
    • Kusatsu – Kyoto 22.2 km is paired by direction: 4 tracks
    • Kyoto – Umekoji – Mukomachi 6.4 km is paired by direction: 5 tracks
    • Mukomachi – Ibaraki 21.8 km is paired by direction: 4 tracks
    • Ibaraki – Suita is paired by use: 6 tracks
    • Suita – Shin-Osaka is paired by use: 8 tracks
    • Shin-Osaka – Osaka – Tsukamoto is paired by direction: 4 tracks
      • (Ibaraki – Osaka 14.6 km)
    • Shin-Osaka – Miyahara – Tsukamoto: 2 tracks
    • Tsukamoto – Hyogo is paired by direction: 4 tracks
    • Hyogo – Takatori is paired by direction: 5 tracks
      • (Osaka – Takatori 38.2 km)
    • Takatori – Nishi-Akashi 17.7 km is paired by use: 4 tracks
  • Between Ochanomizu and Mitaka (JR East) 21.5 km is paired by use.[9]
    • Ochanomizu – Yoyogi: 4 tracks
    • Yoyogi – Shinjuku: 8 tracks
    • Shinjuku – Mitaka: 4 tracks
  • Between Kinshicho and Chiba (JR East) 34.4 km is paired by use.[10]
    • Kinshicho – Nishi-Chiba: 4 tracks
    • Nishi-Chiba – Chiba: 6 tracks
  • Between Ayase and Toride (JR East) 29.7 km: 4 tracks/paired by use[11]
  • Between Osaki and Komagome (JR East) about 20 km is paired by use.[12]
    • Osaki – Yoyogi: 4 tracks
    • Yoyogi – Shinjuku: 8 tracks
    • Shinjuku – Komagome: 4 tracks
  • Between Souen and Heiwa (JR Hokkaido) about 9 km[13]
    • Souen – Sapporo is paired by use: 3 tracks
    • Sapporo – Heiwa is paired by direction: 4 tracks
  • Between Niigata and Kami-Nuttari (JR East) 1.9 km: 4 tracks/paired by direction[14]
  • Between Imamiya and Tennoji (JR West) 2.2 km: 4 tracks/paired by direction[14]
  • Between Inazawa and Nagoya (JR Central) 11.1 km/paired by use: 4 tracks[15]
  • Between Hiroshima and Kaitaichi (JR West) 6.4 km: 4 tracks/paired by direction[16]
  • Between Orio and Moji (JR Kyushu) 24.6 km[17]
    • Orio – Kokura: 4 tracks/paired by use
    • Kokura – Higashi-Kokura 1.6 km/paired by direction: 6 tracks
    • Higashi-Kokura – Moji is paired by direction: 4 tracks
  • Besides JR companies, the following private railway companies in Japan run their own quadruple (or more) tracked sections:

South Korea[edit]



  1. ^ NYC&H RR System Map, circa 1876
  2. ^ New York Central Mileage Chart 1936
  3. ^ Penn Central Transportation Company Track Chart 1975
  4. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 36
  5. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 37
  6. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 10
  7. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 14
  8. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 16
  9. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 20
  10. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 22
  11. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 23
  12. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 24
  13. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 25
  14. ^ a b Japan Railfan Magazine (Koyusha) No. 478 p. 26
  15. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 27
  16. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 28
  17. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 29