Rail transport

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Railway tracks running through Stanhope railway station in North East England, UK.

A railway yard in Portland, Oregon.

Rail transport is the transport of passengers and goods by means of wheeled vehicles specially designed to run along railways or railroads. Rail transport is part of the logistics chain, which facilitates the international trading and economic growth in most countries.

A typical railway/railroad track consists of two parallel rails, normally made of steel, secured to cross-beams, termed [[railroad tie|sleepers],U.K., or 'ties' (U.S.). The sleepers maintain a constant distance between the two rails; a measurement known as the 'gauge' of the track. To maintain the alignment of the track, it is either laid on a bed of ballast or else secured to a solid concrete foundation, and the whole is referred to as Permanent way.

Railway rolling stock, which is fitted with metal wheels, moves with low frictional resistance when compared to road vehicles; on the other hand locomotives and power cars normally rely solely for traction on the point of contact of the wheel with the rail whence they obtain adhesion i.e. the part of the transmitted axle load that makes the wheel "adhere" to the smooth rail. Whilst this is usually sufficient under normal dry rail conditions, adhesion can be reduced or even lost through the presence of unwanted material on the rail surface, such as grease, ice or dead leaves.

• 1 General
• 2 History
  • 2.1 Electrification
• 3 Operations
  • 3.1 Signalling
  • 3.2 Right of way
  • 3.3 Safety and railway disasters
• 4 Trackage
  • 4.1 Track components
  • 4.2 Points (Turnouts or Switches)
  • 4.3 Maintenance
• 5 Terminology
• 6 Rail transport by country
• 7 Gallery
• 8 See also
• 9 Footnotes
• 10 References
• 11 Further reading

[edit] General

A railway ticket issued in the United Kingdom.

Rail transport is an energy-efficient and capital-intensive means of mechanized land transport and is a component of logistics. Rails, which along with various engineered components, are part of the permanent way. They provide very smooth and hard surfaces on which the wheels of the train may roll with a minimum of friction. As an example, a typical modern wagon can hold up to 125 tons of freight on two four-wheel bogies/trucks (100 tons in UK). The contact area between each wheel and the rail is tiny, a strip no more than a few millimetres wide, and hence suffers very little friction. Furthermore, the track distributes the weight of the train evenly, allowing significantly greater loads per axle / wheel than in road transport, leading to less wear and tear on the permanent way. This can save energy compared with other forms of transportation, such as road transport which depends on the friction between rubber and road. Trains also have a small frontal area in relation to the load they are carrying, which cuts down on forward air resistance and thus energy usage, although does not necessarily account for the effect of side winds. In all, under the right circumstances, a train needs 50-70% less energy to transport a given tonnage of freight (or given number of passengers), than does road transport.

Due to these various benefits, rail transport is a major form of public transport in many countries. In Asia, for example, many millions use trains as regular transport in India, China, South Korea and Japan. It is also widespread in European countries. By comparison, intercity rail transport in the United States is relatively scarce outside the Northeast Corridor, although a number of major U.S. cities have heavily-used, local rail-based passenger transport systems or light rail or commuter rail operations.^[1]

The vehicles traveling on the rails are arranged in a series of individual powered or unpowered vehicles linked together, called a train; this can include the locomotive where present. A locomotive (or 'engine') is a powered vehicle used to haul a train of unpowered vehicles; calling a locomotive a "train" is a common popular misnomer. A string of unpowered vehicles without the locomotive is also termed a train; in the U.S.A. individual unpowered vehicles are known as cars (a generic term), and are divided according to the role: for a passenger-carrying vehicle the term carriage (or coach) is used, whilst a freight-carrying vehicle is known as a freight car; in Britain, a freight car would be called a wagon (or a truck). An individual powered passenger vehicle is known as a railcar or a power car; when one or more as these are coupled to one or more unpowered trailer cars as an inseparable unit, this is called a railcar set; several sets coupled together make up a multiple unit. Collectively, rail vehicles of all types are known as rolling stock.

An intercity passenger train (left) and freight train (right) in Great Britain.

[edit] History