The main line, or mainline in American English, of a

railway 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 track that is used for through trains or is the principal artery of the system from which

branch line A branch line is a secondary railway line which branches off a more important through route, usually a main line. A very short branch line may be called a spur line. Branch lines may serve one or more industries, or a city or town not located ...

yards The yard (symbol: yd) is an English unit of length in both the British imperial and US customary systems of measurement equalling 3 feet or 36 inches. Since 1959 it has been by international agreement standardized as exactly ...

, sidings, and spurs are connected. It generally refers to a route between towns, as opposed to a route providing suburban or metro services. It may also be called a trunk line, for example the

Grand Trunk Railway The Grand Trunk Railway (; ) was a Rail transport, railway system that operated in the Provinces and territories of Canada, Canadian provinces of Quebec and Ontario and in the List of states and territories of the United States, American sta ...

in Canada, or the

Trunk Line In telecommunications, trunking is a technology for providing network access to multiple clients simultaneously by sharing a set of circuits, carriers, channels, or frequencies, instead of providing individual circuits or channels for each clie ...

in Norway. For capacity reasons, main lines in many countries have at least a

double track A double-track railway usually involves running one track in each direction, compared to a single-track railway where trains in both directions share the same track. Overview In the earliest days of railways in the United Kingdom, most li ...

and often contain multiple parallel tracks. Main line tracks are typically operated at higher speeds than branch lines and are generally built and maintained to a higher standard than yards and branch lines. Main lines may also be operated under shared access by a number of railway companies, with sidings and branches operated by private companies or single railway companies.

Railway points A railroad switch ( AE), turnout, or (set of) points ( CE) is a mechanical installation enabling railway trains to be guided from one track to another, such as at a railway junction or where a spur or siding branches off. Design T ...

(UK) or switches (US) are usually set in the direction of the main line by default. Failure to do so has been a factor in several fatal railway accidents, for example the

Buttevant Rail Disaster The Buttevant Rail Disaster was a train crash that occurred on 1 August 1980 at Buttevant Railway Station, County Cork, in Ireland, from Dublin on the main line to Cork. More than 70 people were injured, and 18 died, in one of Ireland's wors ...

in Ireland, and the Graniteville train crash in the US.

References

Rail transport operations Railway line types {{Rail-transport-stub