Quadruple track

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.

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

Disadvantages of quadruple track

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:

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.

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

The Americas


Great Britain

Quadruple track section of the Midland Main Line, England











Huning Lines

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

Hong Kong



Four track stretch of the Keihan Main Line in Japan

South Korea




  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. 1 2 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
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