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

  • 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

  • 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

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 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.

  • 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

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



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.




  • The Berlin Stadtbahn, Germany, has four tracks. Two are for the separated S-Bahn and two for mainline trains.
  • The 112 km long Hamm–Minden railway between Hamm and Minden in Germany is completely quadruple-track with separate tracks for freight and passenger trains.
  • The 50 km long railway from Rastatt to Offenburg in Germany has four tracks.
  • The Hohenzollern Bridge, with six tracks
  • The line from Munich to Augsburg has four tracks and near Munich even more



  • The Rome–Naples high-speed railway and the Rome–Sulmona–Pescara railway in Italy combine to form a quadruple track section between Roma Prenestina railway station and Salone railway station.
  • The main section of Ferrovie Nord Milano line between Milan and Saronno in Italy. Outer regional trains are segregated from the inner suburban trains.



  • All of the mainline railway through Stockholm County (between Järna and north of Märsta, 83 km (52 mi)) has four tracks, sometimes having two routes. There are plans to widen Stockholm–Bålsta; north of Märsta–Uppsala and MalmöLund to quadruple track with parts finished or under construction. After this, the Stockholm commuter rail would have its own tracks everywhere.


  • The 120 km long railway from Zürich to Olten contains long quadruple track sections from Zürich to Killwangen-Spreitenbach and from Rupperswil to Aarau, currently being extend to Olten.

United Kingdom

Quadruple track section of the Midland Main Line, England

The Americas



Huning Lines

Hong Kong

  • 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





  1. ^ "New York Central and Hudson River Railroad". www.history-map.com. 
  2. ^ "New York Central Mileage Chart 1936" (PDF). multimodalways.org. 
  3. ^ "Penn Central Transportation Company Track Chart 1975" (PDF). multimodalways.org. 
  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