Single-track railway

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A Class 158 DMU on the Kyle of Lochalsh Line, a primarily single-track railway in Scotland
A train on the Jinhua–Wenzhou Railway, a single-track railway in Southern Zhejiang Province, China

A single-track railway is a railway where trains traveling in both directions share the same track. Single track is usually found on lesser-used rail lines, often branch lines, where the level of traffic is not high enough to justify the cost of constructing a second track.

Advantages and disadvantages[edit]

Single track is significantly cheaper to build, but has operational and safety disadvantages. For example, a single-track line that takes 15 minutes to travel through would have capacity for only two trains per hour in each direction. By contrast, a double track with signal boxes four minutes apart can allow up to 15 trains per hour in each direction, provided all the trains travel at the same speed. This hindrance on the capacity of a single track may be partly overcome by making the track one-way on alternate days, if the single track is not used for public passenger transit.

Long freight trains are a problem if the passing stretches are not long enough. Other disadvantages include the propagation of delays, since one delayed train on a single track will also delay any train waiting for it to pass. Also, a single track does not have a "reserve" track that can allow a reduced capacity service to continue if one track is closed.

Single-track operations[edit]

Passing loops[edit]

Passing Loop

If a single-track line is designed to be used by more than one train at a time, it must have passing loops (also called passing sidings or crossing loops) at intervals along the line to allow trains running in different directions to pass each other. These consist of short stretches of double track, usually long enough to hold one train. The capacity of a single-track line is determined by the number of passing loops. Passing loops may also be used to allow trains heading in the same direction at different speeds to overtake.


Safety operations[edit]



Doubling and singling[edit]

Converting a single-track railway to double track is called duplication or doubling; converting double track to single track is known as singling. A double-track railway operating only a single track is known as single-line working.

New bike paths and railway corridors[edit]



  1. ^ "E&N Rail Trail-Humpback Connector". 4 September 2013. Archived from the original on 22 June 2012.

External links[edit]