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A single-track railway is a railway where trains traveling in both directions share the same track. Single track is usually found on lesser-used rail lines, often branch lines, where the level of traffic is not high enough to justify the cost of constructing a second track.
Single track is significantly cheaper to build and maintain, but has operational and safety disadvantages. For example, a single-track line that takes 15 minutes to travel through would have capacity for only two trains per hour in each direction. By contrast, a double track with signal boxes four minutes apart can allow up to 15 trains per hour in each direction, provided all the trains travel at the same speed. This hindrance on the capacity of a single track may be partly overcome by making the track one-way on alternate days, if the single track is not used for public passenger transit.
Long freight trains are a problem if the passing stretches are not long enough. Other disadvantages include the propagation of delays, since one delayed train on a single track will also delay any train waiting for it to pass. Also, a single track does not have a "reserve" track that can allow a reduced capacity service to continue if one track is closed.
If a single-track line is designed to be used by more than one train at a time, it must have passing loops (also called passing sidings or crossing loops) at intervals along the line to allow trains running in different directions to pass each other. These consist of short stretches of double track, usually long enough to hold one train. The capacity of a single-track line is determined by the number of passing loops. Passing loops may also be used to allow trains heading in the same direction at different speeds to overtake.
In some circumstances on some isolated branch lines with a simple shuttle service (such as the Abbey Line in Great Britain) a single-track line may work under the "one train working" principle without passing loops, where only one train is allowed on the line at a time.
On single-track lines with passing loops, measures must be taken to ensure that only one train in one direction can use a stretch of single track at a time, as head-on collisions are a particular risk. Some form of signalling system is required. In traditional British practice (and countries using British practice), single-track lines were operated using a token system where the train driver had to be in possession of a token in order to enter a stretch of single track. Because there was only one unique token issued at any one time for each stretch of single track, it was impossible for more than one train to be on it at a time. This method is still used on some minor lines but in the longest single-track lines in Britain (e.g. the Highlands of Scotland) this has been superseded by radio communication.
In the early days of railways in North America it was common to rely upon simple timetable operation where operators knew where a train was scheduled to be at a particular time, and so would not enter a single-track stretch when they were not scheduled to. This generally worked but was inflexible and inefficient. It was improved with the invention of the telegraph and the ability to issue train orders.
Converting a single-track railway to double track is called duplication or doubling; converting double track to single track is known as singling. A double-track railway operating only a single track is known as single-line working. Kirkby railway station (until 1977) and Ormskirk railway station (until 1970) were double-track railway, when they were converted into single track railway with cross-platform interchange.
Building bike trails on rail corridors has occurred in limited examples, however developing rail right of ways for a bike trail can restrict a train corridor to a single track. Also reclaiming a railway corridor to use trains again, that have become bike paths, limits the use of double tracks. The bike path is usually where the second track would be. An example of a bike, single-track corridor is the E&N Railway in Victoria, Canada.
A railroad switch (AE), turnout, or [set of] points (BE) 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.
In railway signalling, a token is a physical object which a train driver is required to have or see before entering onto a particular section of single track. The token is clearly endorsed with the names of the section it belongs to. A token system is more commonly used for single lines because of the greater risk of collision in the event of a mistake being made by a signaller or traincrew, than on double lines.
The Main North Line is a major railway in New South Wales, Australia. It runs through the Central Coast, Hunter and New England regions. The line was the original main line between Sydney and Brisbane, however this required a change of gauge at Wallangarra. As of 1988, the line closed progressively north of Armidale with services gradually withdrawn till 2004, with the main route between Sydney and Brisbane now the North Coast line.
Radio Electronic Token Block is a system of railway signalling used in the United Kingdom. It is a development of the physical token system for controlling traffic on single lines.
The Looe Valley Line is an 8 3⁄4 miles (14 km) community railway from Liskeard to Looe in Cornwall, United Kingdom, that follows the valley of the East Looe River for much of its course. It is operated by Great Western Railway.
The Esk Valley line is a railway line approximately 35 miles (56 km) long from Middlesbrough to Whitby in North Yorkshire, England. The route follows the course of the River Esk for much of its eastern half.
Gauntlet track or interlaced track is an arrangement in which railway tracks run parallel on a single track bed and are interlaced such that only one pair of rails may be used at a time. Since this requires only slightly more width than a single track, all rails can be carried on the same crossties/sleepers. Trains run on the discrete pair of rails appropriate to their direction, track gauge or loading gauge.
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.
A passing loop or passing siding is a place on a single line railway or tramway, often located at or near a station, where trains or trams travelling in opposite directions can pass each other. Trains/trams going in the same direction can also overtake, provided that the signalling arrangement allows it. A passing loop is double-ended and connected to the main track at both ends, though a dead end siding known as a refuge siding, which is much less convenient, can be used. A similar arrangement is used on the gauntlet track of cable railways and funiculars, and in passing places on single-track roads.
The West Wales lines are a group of railway lines from Swansea through Carmarthenshire to Pembrokeshire, West Wales. The main part runs from Swansea to Carmarthen and Whitland, where it becomes three branches to Fishguard, Milford Haven and Pembroke Dock.
A level junction 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 of opposing traffic at grade.
Signalling block systems enable the safe and efficient operation of railways by preventing collisions between trains. The basic principle is that a route is broken up into a series of blocks, only one train may occupy a block at a time, and that the blocks are sized to allow a train to stop within them. This ensures that a train always has time to stop before reaching another train on the same line. A block system is referred to as the method of working in the UK, method of operation in the US and safeworking in Australia.
The Chrysler Canada Greenway is a 42 km-long rail trail in Essex County, Ontario, Canada, stretching from Oldcastle to Leamington.
Opened on the 8th of October 1998, the only high-speed rail in Norway, on the railways of Norway is on Gardermobanen, a 64 kilometer line between Oslo Central Station and Eidsvoll via Oslo Airport. The main service on this route is Flytoget, commuting between Oslo Airport and the metropolitan areas of Oslo at speeds of up to 210 km/h (130 mph). It was extended westwards to include the city of Drammen in 2008, though not at high speed. The high-speed section is also used by express and regional trains between Oslo and Eidsvoll.
The Coventry to Leamington Line is a railway line linking the city of Coventry with the town of Leamington Spa. The line was opened in 1844 by the London and Birmingham Railway, as far as Milverton. The line was extended to Leamington Spa Avenue in 1851. A connecting line to Berkswell opened in 1884.
Automatic block signaling (ABS) is a railroad communications system that consists of a series of signals that divide a railway line into a series of sections, or "blocks". The system controls the movement of trains between the blocks using automatic signals. ABS operation is designed to allow trains operating in the same direction to follow each other in a safe manner without risk of rear-end collision. The introduction of ABS reduced railways' costs and increased their capacity. Older manual block systems required human operators. The automatic operation comes from the system's ability to detect whether blocks are occupied or otherwise obstructed, and to convey that information to approaching trains. The system operates without any outside intervention, unlike more modern traffic control systems that require external control to establish a flow of traffic.
The Follo Line is a planned 22.5-kilometer (14.0 mi) high-speed railway between Oslo and Ski, Norway. Running parallel to the Østfold Line, it will be engineered for 250 km/h (155 mph). Terminal stations will be Oslo Central Station and Ski Station. Most of the line, 19 kilometres (12 mi), will be in a single tunnel, which will be the longest railway tunnel in the country. Construction started in 2014, and is estimated to be completed by December 2022. The Follo Line will increase capacity from twelve to forty trains per hour along the South Corridor, and will allow express and regional trains to decrease travel time from Ski to Oslo from 22 to 11 minutes. The line was prospected to cost over 26 billion Norwegian krone (NOK) in 2014.
The Sydney–Melbourne rail corridor is an approximately 960-kilometre (600 mi) standard gauge railway corridor that runs between Melbourne and Sydney, the two largest cities in Australia. Freight and passenger services operate along the route, such as the NSW TrainLink XPT passenger service. The XPT offers a day and night service in each direction.
The application of railway signals on a rail layout is determined by various factors, principally the location of points of potential conflict, as well as the speed and frequency of trains and the movements they require to make.
The Bendigo V/Line rail service is a regional passenger rail service operated by V/Line in Victoria, Australia. It serves passengers between state capital Melbourne, Victoria and the regional city of Bendigo, Victoria.