Pittsburg Center station and pocket track, February 2018

A pocket track, tail track, or reversing siding (UK: centre siding , turnback siding) is a

rail track A railway track (British English and UIC terminology) or railroad track (American English), also known as permanent way or simply track, is the structure on a railway or railroad consisting of the rails, fasteners, railroad ties (sleepers, ...

layout which allows

train In rail transport, a train (from Old French , from Latin , "to pull, to draw") is a series of connected vehicles that run along a railway track and Passenger train, transport people or Rail freight transport, freight. Trains are typically pul ...

s to park off the main line. This type of track layout differs from a

passing loop A passing loop (UK usage) or passing siding (North America) (also called a crossing loop, crossing place, refuge loop or, colloquially, a hole) is a place on a single line railway or tramway, often located at or near a station, where trains or ...

in that the pocket track is usually located between two main lines, rather than off to the side. Pocket tracks also allow for the short-turning of trains, truncating services at an intermediate station to control train frequency. They are also used at

terminal station A train station, railway station, railroad station or depot is a railway facility where trains stop to load or unload passengers, freight or both. It generally consists of at least one platform, one track and a station building providing such ...

s to allow for the construction of future extension of a rail track without disrupting existing service.

References

{{rail-stub Railway sidings