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Quadruple track section of the West Coast Main Line, England

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 or sections. Such conversion is referred to as "quadruplication".

A railway line with six parallel tracks, or a sextuple-track railway, has three tracks in each direction. The corresponding term is "sextuplication".

There are also instances of railway lines or sections with eight tracks, and cases with three or five tracks. All experience similar upsides and downsides.




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:

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. 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.

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 Northern 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. Future passenger and freight-separated track pairs are planned by the state of Virginia on the corridor between Washington, D.C. and Richmond, Virginia,[1] and by California High-Speed Rail between Los Angeles and Fullerton, California.[2]

Two separate double-track lines in proximity to each other, e.g., two double-track lines along opposite sides of a river, can operate as a quadruple track line. Examples of this can be found in Rhone in France and Rhine in Germany.


As it can be seen from the pictures below in the Gallery of diagrams, the four tracks can be paired either by direction (slow and fast in each pair) or by purpose (speed or direction in each pair). Pairing by direction allows the railway to interface to a double track more easily. With fast trains in centre, local stations can be on the outside, eliminating staircases for half the passengers. With slow trains in centre or when pairing by speed there can be a common platform for local trains with one staircase and one ticket booth.

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.




Several lines radiating from Brussels are quadrupled, for instance the Ghent-Ostend line as far as Essene-Lombeek. Further quadrupling has recently been carried out as part of the development of the Brussels Regional Express Network. The building of high-speed lines has also led to quadrupling - for instance the HSL 2 high-speed line between Brussels and Cologne runs inside the local lines as far as Leuven. Meanwhile since 1934 Brussels and Antwerp have been connected by two separate pairs of double track. Fast trains normally use line 25, while line 27 serves slow trains. In places they run parallel, but at times diverge and cross over each other.


There are two places in Denmark with four tracks:



By definition German railway lines have one or two tracks. Where more tracks are running parallel to each other, they are considered two or more separate lines. Such routes include:


Quadrupled section of the Dublin Suburban Rail system




There are some quadruple-track railways in the Oslo region. They are mostly two double tracks with slightly different routes, one older for local trains, and one newer mostly in tunnels for high-speed and regional trains.





United Kingdom

Quadruple track section of the Midland Main Line, England

The Americas



United States

4-track section of Amtrak's Northeast Corridor in New Jersey
East coast
West coast
The four tracks of the Pacific Electric Watts Line in Los Angeles, 1906



Huning Lines

Hong Kong





Four track stretch of the Keihan Main Line in Japan


The country never implemented a quadruple-track line throughout its history, but there are plans for sections of the North–South Commuter Railway (NSCR) to be quadruplicated.

South Korea





Turrella station on the East Hills line

See also


  1. ^ Luczak, Marybeth (March 30, 2021). "Virginia, Amtrak, CSX advance $3.7B rail initiative". Railway Age. ISSN 0033-8826. Retrieved January 24, 2024.
  2. ^ Slaten, Michael (November 1, 2023). "California High-Speed Rail Authority considering adding new track in Southern California corridor". Orange County Register. Retrieved January 22, 2024 – via Transit Talent.
  3. ^ "Rijswijk - Rotterdam". (in Dutch). Retrieved 2023-12-05.
  4. ^ "Spoorverdubbeling Amsterdam – Utrecht". Infrasite (in Dutch). Retrieved 2023-12-05.
  5. ^ "Lund–Arlöv, fyra spår" (in Swedish). Swedish Transport Administration. Retrieved 19 August 2018.
  6. ^ "Western Sectional Appendix June 2022" (PDF). Retrieved 27 July 2022.
  7. ^ "Piccadilly and District line track improvement works continue over the next two weekends".
  8. ^ "New York Central and Hudson River Railroad".
  9. ^ "New York Central Mileage Chart 1936" (PDF).
  10. ^ "Penn Central Transportation Company Track Chart 1975" (PDF).
  11. ^ Gideon, Arthur (14 April 2019). "Senin, Perjalanan KRL Masih Terganggu Pengoperasian Jalur Dwiganda". (in Indonesian). Retrieved 21 January 2022.
  12. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 36
  13. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 37
  14. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 10
  15. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 14
  16. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 16
  17. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 20
  18. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 22
  19. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 23
  20. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 24
  21. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 25
  22. ^ a b Japan Railfan Magazine (Koyusha) No. 478 p. 26
  23. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 27
  24. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 28
  25. ^ Japan Railfan Magazine (Koyusha) No. 478 p. 29
  26. ^ "Sec. A2". Basic Design. The Detailed Design Study (including Supplementary Feasibility Study) of the South Commuter Railway Project Package CP S-03b (Report). Vol. II. Japan International Cooperation Agency, Tokyo Metro, et al. 2021-03-24.
  27. ^ a b "Sec. 6". MCRP Detailed Design. The Detailed Design Study (including Supplementary Feasibility Study) of the Malolos Clark Railway Project Package CP N-04 (Report). Vol. II. Japan International Cooperation Agency, Tokyo Metro, et al. 2019-05-06.