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Headshunt

From Wikipedia, the free encyclopedia
Platform track and run-round loop at Toyooka Station, Hyōgo, Japan, the terminus of the line from Miyazu

A headshunt (or escape track in the United States) is a short length of track provided to release locomotives at terminal platforms, or to allow shunting to take place clear of main lines.

Terminal headshunt

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Sequence at a terminal headshunt:
1. train arrives at the station
2. locomotive is detached from the train and moves into the headshunt
3. locomotive reverses and the points are switched
4. locomotive travels along the passing loop to pass the cars
5. locomotive reverses direction and the points are switched
6. locomotive couples to the opposite end of the train
7. locomotive reverses and the train departs

A 'terminal headshunt' is a short length of track that allows a locomotive to uncouple from its train, move forward, and then run back past it on a parallel track. Such headshunts are typically installed at a terminal station to allow the locomotive of an arriving train to move to the opposite end of (in railway parlance, 'run around') its train so that it can then haul the same train out of the station in the other direction (assuming, of course, that it is a locomotive equipped to run in either direction; for locomotives that only operate in one direction, a wye or turntable needs to be provided to physically turn the engine around, as well as a run-around track).

Reversing headshunt

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Main article: Pocket track
Melbourne University tram stop has three reversing headshunts in succession, between the two running lines.

Found primarily on metro systems, rapid transit light rail networks, and tramways, a 'reversing headshunt' allows certain trains or trams to change direction, even on lines with high traffic flow, whilst others continue through the station.

Shunting neck

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The term headshunt may also refer to shunting neck or 'shunt spur': a short length of track laid parallel to the main line to allow a train to shunt back into a siding or rail yard without occupying the main running-line.[citation needed]

Run round

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This section is about the track arrangement. For heat recovery system, see run around coil.
Diagram of a headshunt and run round loop

A run round loop (or run-around loop) is a track arrangement that enables a locomotive to attach to the opposite end of the train. It is commonly used to haul wagons onto a siding, or at a terminal station to prepare for a return journey.[1] This process is known as "running round a train".[2]

Although a common procedure for passenger trains when the majority of them were locomotive-hauled, the maneuver is now becoming rarer on public service railways.[citation needed] Increased use of multiple unit and push-pull passenger services avoids the requirement for dedicated track and the need for railway staff to detach and reattach the locomotive at track level.[citation needed] However, on heritage railways run-round loops are still usually more or less necessary at each end of the running line, partly because train services are usually locomotive-hauled, and partly because the run-round operation gives added interest to visitors. This practice is still very common on Intercity services in Victoria, Australia.

Runaround tracks are used in freight rail service in order to back cars into spurs or to change directions to keep the locomotive at the front of the train for transport. In this case the runaround track must be as long as the longest set of cars that would be pulled. The locomotive leaves the cars on the runaround track or the main line, goes around, and hooks up to the other end of the train. It can then reverse the cars into a spur.

Examples

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Stations which used to have run-rounds include:

  • Turntable and run round loop at Withernsea
    Turntable and run round loop at Withernsea
  • Leeds Central station showing the release crossovers
    Leeds Central station showing the release crossovers

Stations which still have run-rounds include:

No loop

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If a terminal station does not have a run-round loop trains are restricted to multiple units or Top and Tail trains.[citation needed]

See also

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References

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  1. ^ Jackson, Alan A. (2006). The Railway Dictionary (4th ed.). Sutton Publishing Ltd. p. 298. ISBN 0-7509-4218-5.
  2. ^ Ellis, Iain (2006). Ellis' British Railway Engineering Encyclopaedia. Lulu.com. p. 307. ISBN 978-1-8472-8643-7.
  3. ^ "View map: Edinburghshire III.8 (Edinburgh) - Ordnance Survey 25 inch 2nd and later editions, Scotland, 1892-1949". maps.nls.uk.
  4. ^ Edinburgh Waverley station - NBR Co. plan - published ca. 1898 - zoomed in
  5. ^ Edinburgh Waverley on OS town plan (1887) showing 3-way release crossover points between platforms
  6. ^ Edinburgh Waverley on OS town plan (1894) showing 3-way release crossover points between platforms 2 & 3 and 4 & 5
  7. ^ Manchester Central on OS 1:500 town plan (1888) showing 3-way release crossover points between platforms 1 & 2, 3 & 4 and 5 & 6
  8. ^ Manchester Central station - Ordnance Survey 25" to the mile - published 1934
  9. ^ Manchester Central station looking towards the buffer stops (Disused Stations in the UK)
  10. ^ Manchester Central station from the buffer stops (Disused Stations in the UK)
  11. ^ 1864 - 1:500 town plan (Disused Stations)
  12. ^ Liverpool Exchange on OS 1:500 town plan (1890) showing 3-way release crossover points between platforms 4 & 5
  13. ^ Preston Hendry, R., Powell Hendry, R., (1982) An historical survey of selected LMS stations : layouts and illustrations. Vol. 1 Oxford Publishing
  14. ^ Leeds Central station from the buffer stops showing 3-way point for release crossovers
  15. ^ Leeds Central on OS 1:500 town plan (1910) showing 3-way release crossover points between platforms 2 & 3
  16. ^ "Moor Street Passenger Station". Warwickshirerailways.com. Retrieved 24 March 2013.
  17. ^ "Moor Street Station: Ex-GWR 2-6-2T 'Prairie' No 6152 is seen standing on the traverser as it is being moved from platform 2 to platform 1 on the right". Warwickshirerailways.com.
  18. ^ A locomotive at Moor Street being transferred to the run round loop for platform 3 (Warwickshirerailways.com)
  19. ^ "Station Name: Withernsea". Disused Stations. Subterranea Britannica. 19 April 2019. Retrieved 8 March 2022.
  20. ^ 1891 1:2,500 OS map showing the layout of Withernsea station (Disused Stations in the UK)
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