A junction, in the context of

rail transport Rail transport (also known as train transport) is a means of transport using wheeled vehicles running in railway track, tracks, which usually consist of two parallel steel railway track, rails. Rail transport is one of the two primary means of ...

, is a place at which two or more rail routes converge or diverge. The physical connection between the tracks of the two routes (assuming they are of the same gauge) is provided by turnouts (US:

switch In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type o ...

es) and

signalling A signal is both the process and the result of transmission of data over some media accomplished by embedding some variation. Signals are important in multiple subject fields including signal processing, information theory and biology. In ...

Overview

In a simple case where two routes with one or two tracks each meet at a junction, a fairly simple layout of tracks suffices to allow trains to transfer from one route to the other. More complicated junctions are needed to permit trains to travel in either direction after joining the new route – for example by providing a triangular track layout.In this latter case, the three points of the triangle may be given different names, for example using points of the compass as well as the name of the overall place.

Rail transport operations Rail transport operations are the day-to-day operations of a railway. A railway has two major components: the infrastructure (the permanent way, tracks, stations, freight facilities, viaducts, tunnels, etc.) and the rolling stock (the passenger ...

refer to stations that lie on or near a railway junction as a ''

junction station ''Junction station'' usually refers to a railway station situated either on or close to a rail junction, where lines to two or more destinations diverge. Many junction stations have multiple platform faces to enable trains for multiple destinatio ...

''. In the UK it is customary for the junction (and the related station) to be named after the next station on the branch, e.g. Yeovil Junction is on the mainline railway south of

Yeovil Yeovil () is a town and civil parishes in England, civil parish in Somerset, England. It is close to Somerset's southern border with Dorset, west of London, south of Bristol, west of Sherborne and east of Taunton. The population of the bui ...

, and the next destination on the branch is Yeovil Pen Mill. Frequently, trains are built up and taken apart (separated) at such stations so that the same train can be divided and proceed to multiple destinations. For goods trains (US: freight trains), marshalling yards (US: Classification yards) serve a similar purpose.

Measures to improve junction capacity

The capacity of the junctions limits the capacity of a railway network more than the capacity of individual railway lines. This applies more as the network density increases. Measures to improve junctions are often more useful than building new railway lines. The capacity of a railway junction can be increased with improved signaling measures, by building points suitable for higher speeds, or by turning

level junction A level junction (or in the United Kingdom a flat crossing) is a railway junction that has a track configuration in which merging or crossing railroad lines provide track connections with each other that require trains to cross over in front o ...

s into

flying junction A flying junction or flyover is a railway junction at which one or more diverging or converging tracks in a multiple-track route cross other tracks on the route by bridge to avoid conflict with other train movements. A more technical term is "gr ...

s, where tracks are

grade-separated In civil engineering (more specifically highway engineering), grade separation is a method of aligning a junction of two or more surface transport axes at different heights ( grades) so that they will not disrupt the traffic flow on other tr ...

, and so one track passes over or under another. With more complicated junctions such construction can rapidly become very expensive, especially if space is restricted by

tunnel A tunnel is an underground or undersea passageway. It is dug through surrounding soil, earth or rock, or laid under water, and is usually completely enclosed except for the two portals common at each end, though there may be access and ve ...

bridge A bridge is a structure built to Span (engineering), span a physical obstacle (such as a body of water, valley, road, or railway) without blocking the path underneath. It is constructed for the purpose of providing passage over the obstacle, whi ...

s or inner-city tracks.

Avoiding the need for junctions

The installation of junctions into a rail system poses many challenges, including increased maintenance costs, and problems in on-time performance. Metro rail systems have a rail network design where the number of junctions is minimized. Passengers, and not trains, move from one

train station A train station, railroad station, or railway station 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 suc ...

to another.

Gallery

File:Track of Singapore LRT 002.jpg, Junction in track of Singapore LRT File:Cardiff Queen Street - view north - 02.jpg, A double junction in

Cardiff Cardiff (; ) is the capital city, capital and List of urban areas in the United Kingdom, largest city of Wales. Cardiff had a population of in and forms a Principal areas of Wales, principal area officially known as the City and County of Ca ...

Wales Wales ( ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by the Irish Sea to the north and west, England to the England–Wales border, east, the Bristol Channel to the south, and the Celtic ...

File:Baranowicze WIG 1934.jpg, A junction in

Baranowicze Baranavichy or Baranovichi is a city in the Brest Region of western Belarus. It serves as the administrative center of Baranavichy District, though it is administratively separated from the district. As of 2025, it has a population of 170,817. ...

, Poland, 1934 (since 1939 in

Belarus Belarus, officially the Republic of Belarus, is a landlocked country in Eastern Europe. It is bordered by Russia to the east and northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Belarus spans an a ...

) File:KatniJunctionMadhyaPradesh2010.jpg, A train passing through Katni Junction in Madhya Pradesh, India

Notes

References

External links

* {{DEFAULTSORT:Junction (Rail) Train-related introductions in 1831 1831 in rail transport 1831 establishments in England Railway track layouts Permanent way