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

railway Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a pre ...

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

branch lines A branch line is a phrase used in railway terminology to denote 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. Industrial spur An industr ...

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 (; french: Grand Tronc) was a railway system that operated in the Canadian provinces of Quebec and Ontario and in the American states of Connecticut, Maine, Michigan, Massachusetts, New Hampshire, and Vermont. The rai ...

in Canada, 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, and the Trunk Line Bridge No. 237 in the United States. For capacity reasons, main lines in many countries have at least a double track 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 (), turnout, or ''set ofpoints () 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. The most common ty ...

(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 Classification of railway accidents, both in terms of cause and effect, is a valuable aid in studying rail (and other) accidents to help to prevent similar ones occurring in the future. Systematic investigation for over 150 years has led to the r ...

, for example the Buttevant Rail Disaster in Ireland, and the Graniteville train disaster in the US.

References

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