A train is a form of transport consisting of a series of connected vehicles that generally runs along a railroad track to transport cargo or passengers. The word "train" comes from the Old French trahiner, derived from the Latin trahere meaning "to pull" or "to draw".
Motive power for a train is provided by a separate locomotive or individual motors in a self-propelled multiple unit. Although historically steam propulsion dominated, the most common types of locomotive are diesel and electric, the latter supplied by overhead wires or additional rails. Trains can also be hauled by horses, pulled by engine or water-driven cable or wire winch, run downhill using gravity, or powered by pneumatics, gas turbines or batteries.
The track usually consists of two running rails with a fixed spacing, which may be supplemented by additional rails such as electric conducting rails and rack rails. Monorails and maglev guideways are also used occasionally.
A passenger train includes passenger-carrying vehicles and can often be very long and fast. One notable and growing long-distance train category is high-speed rail. To achieve much faster operation at speeds of over 500 km/h (310 mph), innovative maglev technology has been the subject of research for many years. The term "light rail" is sometimes used to refer to a modern tram system, but it may also mean an intermediate form between a tram and a train, similar to a heavy rail rapid transit system. In most countries, the distinction between a tramway and a railway is precise and defined in law.
A freight train (or goods train) uses freight cars (or wagons/trucks) to transport goods or materials (cargo). It is possible to carry passengers and freight in the same train using a mixed consist.
Rail cars and machinery that are used for the maintenance and repair of tracks, are termed "maintenance of way" equipment; these may be assembled into maintenance of way trains. Similarly, dedicated trains may be used to provide support services to stations along a train line, such as garbage or revenue collection.
There are various types of train that are designed for particular purposes.
A passenger train consists of one or more locomotives and (usually) several coaches.
In the United Kingdom, a train hauled using two locomotives is known as a "double-headed" train.
The railway terminology that is used to describe a train varies between countries.
In the United Kingdom, the interchangeable terms set and unit are used to refer to a group of permanently or semi-permanently coupled vehicles, such as those of a multiple unit. While when referring to a train made up of a variety of vehicles, or of several sets/units, the term formation is used. (Although the UK public and media often forgo formation, for simply train.) The word rake is also used for a group of coaches or wagons.
Section 83(1) of the UK's Railways Act 1993 defines "train" as follows:
In North America, the term consist (/ˈkɒnsɪst/ KON-sist]]istlocomotives powering the train. Similarly, the term trainsetfers to a group of rolling stock that is permanently or semi-permanently coupled together to form a unified set of equipment (the term is most often applied to passenger train configurations).
There are three types of locomotive: electric, diesel and steam.
The Atchison, Topeka and Santa Fe Railway's 1948 operating rules define a train as: "An engine or more than one engine coupled, with or without cars, displaying markers."
A bogie (/ˈboʊɡi/ BOH-ghee) is a wheeled wagon or trolley. In mechanics terms, a bogie is a chassis or framework carrying wheels, attached to a vehicle. It can be fixed in place, as on a cargo truck, mounted on a swivel, as on a railway carriage or locomotive, or sprung as in the suspension of a caterpillar tracked vehicle. Usually, two bogies are fitted to each carriage, wagon or locomotive, one at each end. An alternate configuration, which is often used in articulated vehicles, places the bogies (often Jacobs bogies) under the connection between the carriages or wagons. Most bogies have two axles, as this is the simplest design, but some cars designed for extremely heavy loads have been built with up to five axles per bogie. Heavy-duty cars may have more than two bogies using span bolsters to equalize the load and connect the bogies to the cars. Usually, the train floor is at a level above the bogies, but the floor of the car may be lower between bogies, such as for a double decker train to increase interior space while staying within height restrictions, or in easy-access, stepless-entry, low-floor trains.
The first trains were rope-hauled, gravity powered or pulled by horses, but from the early 19th century almost all trains were powered by steam locomotives. From the 1910s onwards, steam locomotives began to be replaced with less labor-intensive (and cleaner) diesel and electric locomotives, although these new forms of propulsion were far more complex and expensive than steam power. At about the same time, self-propelled multiple unit vehicles (both diesel and electric) became much more widely used in passenger service. Dieselization of locomotives in day-to-day use was completed in most countries by the 1970s. Steam locomotives are still used in heritage railways which are operated in many countries for the leisure and enthusiast market.
Electric traction offers a lower cost per mile of train operation but at a higher initial cost, which can only be justified on high traffic lines.
Lesser used locomotives are: gas turbine locomotive and fuel cell locomotives, which combine the advantage of not needing an electrical system in place, with the advantage of emissionless operation. However, there is a substantial initial cost associated with fuel cell vehicles.
A passenger train includes passenger-carrying vehicles and can often be very long and fast.
Unlike freight trains, passenger trains must supply head-end power to each coach for lighting and heating, among other purposes. This can be drawn directly from the locomotive's prime mover (modified for the purpose), or from a separate diesel generator in the locomotive. For passenger service on remote routes where a head-end-equipped locomotive may not always be available, a separate generator van may be used.
Oversight of a passenger train is the responsibility of the conductor. He or she is sometimes assisted by other crew members, such as service attendants or porters. During the heyday of North American passenger rail travel, long distance trains carried two conductors: the aforementioned train conductor, and a Pullman conductor, the latter being in charge of sleeping car personnel.
Many prestigious passenger train services have been given a specific name, some of which have become famous in literature and fiction. In past years, railroaders often referred to passenger trains as the "varnish", alluding to the bygone days of wooden-bodied coaches with their lustrous exterior finishes and fancy livery. "Blocking the varnish" meant a slow-moving freight train was obstructing a fast passenger train, causing delays.
Some passenger trains, both long distance and short distance, may use bi-level (double-decker) cars to carry more passengers per train. Car design and the general safety of passenger trains have dramatically evolved over time, making travel by rail remarkably safe.
Long-distance trains travel between many cities and/or regions of a country, and sometimes cross several countries.
One notable and growing long-distance train category is high-speed rail.
The fastest wheeled train running on rails is France's TGV (Train à Grande Vitesse, literally "high speed train"), which achieved a speed of 574.8 km/h (357.2 mph), twice the takeoff speed of a Boeing 727 jetliner, under test conditions in 2007. The highest speed currently attained in scheduled revenue operation is 350 km/h (220 mph) on the Beijing–Tianjin Intercity Rail and Wuhan–Guangzhou High-Speed Railway systems in China. The TGV runs at a maximum revenue speed of 300–320 km/h (190–200 mph), as does Germany's Inter-City Express and Spain's AVE (Alta Velocidad Española).
In most cases, high-speed rail travel is time- and cost-competitive with air travel when distances do not exceed 500 to 600 km (310 to 370 mi), as airport check-in and boarding procedures may add as many as two hours to the overall transit time. Also, rail operating costs over these distances may be lower when the amount of fuel consumed by an airliner during takeoff and climbout is considered. As travel distance increases, the latter consideration becomes less of the total cost of operating an airliner and air travel becomes more cost-competitive.
Some high-speed rail equipment employs tilting technology to improve stability in curves. Examples of such equipment are the Advanced Passenger Train (APT), the Pendolino, the N700 Series Shinkansen, Amtrak's Acela Express and the Talgo. Tilting is a dynamic form of superelevation, allowing both low- and high-speed traffic to use the same trackage (though not simultaneously), as well as producing a more comfortable ride for passengers.
"Inter-city" is a general term for any rail service that uses trains with limited stops to provide fast long-distance travel.
- InterCity: using high-speed trains to connect cities, bypassing all intermediate stations, thus linking major population hubs in the fastest time possible
- Regional: calling at all intermediate stations between cities, serving smaller communities along the route
The distinction between the three types of inter-city rail service may be unclear; trains can run as InterCity services between major cities, then revert to an express (or even regional) train service to reach communities at the extremity of the journey. This practice allows marginal communities to be served in the most cost-effective way, at the expense of a longer journey time for those wishing to travel to the terminus station.
Regional trains usually connect between towns and cities, serving smaller urban (and some rural) communities en route. These services are provided to meet local traffic demand in less accessible areas.
Higher-speed rail is a special category of trains.
For shorter distances many cities have networks of commuter trains (also known as suburban trains) serving the city and its suburbs. Trains are a very efficient mode of transport to cope with large traffic demand in a metropolis. Compared with road transport, it carries many people with much smaller land area and little air pollution. Commuter rail also travels longer ranges compared to rapid transit systems with comparatively less frequency and may share tracks with other trains.
Some carriages may be laid out to have more standing room than seats, or to facilitate the carrying of prams, cycles or wheelchairs. Some countries have double-decked passenger trains for use in conurbations. Double deck high speed and sleeper trains are becoming more common in mainland Europe.
Sometimes extreme congestion of commuter trains becomes a problem.
Passenger trains usually have emergency brake handles (or a "communication cord") that the public can operate. Misuse is punished by a heavy fine.
Various commuter and suburban train operators (e.g. Sydney Trains, NJ Transit, Paris RER) use double-decker trains. Double-decker trains offer increased capacity even when running less services.
Large cities often have a rapid transit system, also called "metro", "underground", "subway" or "tube".
The general term "rapid transit" is used for public transport such as commuter trains, metro and light rail.
In the UK, the distinction between a tramway and a railway is precise and defined in law.
The length of a tram or trolley may be determined by national regulations.
The term "light rail" is sometimes used for a modern tram system, despite light rail lines commonly having a mostly exclusive right-of-way, more similar to that of a heavy-rail line and less like that of a tramway.
Monorails were developed to meet medium-demand traffic in urban transit, and consist of a train running on a single rail, typically elevated.
To achieve much faster operation over 500 km/h (310 mph), innovative maglev technology has been researched since the early 20th century.
The Shanghai Maglev Train, opened in 2003, is the fastest commercial train service of any kind, operating at speeds of up to 430 km/h (270 mph). Maglev has not yet been used for inter-city mass transit routes.
A railcar, in British English and Australian English, is a self-propelled railway vehicle designed to transport passengers. The term "railcar" is usually used in reference to a train consisting of a single coach (carriage, car), with a driver's cab at one or both ends. Some railways, e.g., the Great Western Railway, used the term Railmotor. If it is able to pull a full train, it is rather called a motor coach or a motor car. The term is sometimes also used as an alternative name for the small types of multiple unit which consist of more than one coach.
Railway companies often give a name to a train service as a marketing exercise, to raise the profile of the service to attract more passengers (and also to gain recognition for the company).
The names of special passenger trains have passed into popular culture: the Orient Express, Flying Scotsman, Golden Arrow, and Royal Scot are examples of famous British trains; the Texas Eagle and California Zephyr are particularly well-known in the US; and the Red Arrow is a celebrated Russian sleeper train. In India, some of the popular specially-named train services are the Brindavan Express (Chennai–Bengaluru), Deccan Queen (Mumbai CST–Pune), and Flying Ranee (Mumbai Central–Surat).
A somewhat less common practice is the naming of freight trains, for the same commercial reasons.
Airport trains transport people between terminals within an airport complex.
Heritage trains are operated by volunteers, often railfans, as a tourist attraction. Usually trains are formed from historic vehicles retired from national commercial operation.
Mine trains are operated in large mines and carry both workers and goods.
Overland trains are used to carry cargo over rough terrain.
A freight train (or "goods train") uses freight cars or wagons (also known as "trucks" or "goods wagons") to transport goods or materials (cargo) – essentially any train that is not used for carrying passengers. Much of the world's freight is transported by train, and the rail system in the US is used mostly for transporting freight rather than passengers.
Under the right circumstances, transporting freight by train is highly economic, and also more energy efficient than transporting freight by road.
The main disadvantage of rail freight is its lack of flexibility and for this reason, rail has lost much of the freight business to road competition. Many governments are trying to encourage more freight back onto trains because of the benefits that it would bring.
There are many different types of freight train, used for carrying a huge variety of different kinds of freight, with various types of wagon. One of the most common types on modern railways are intermodal (container) trains, where the containers can be lifted on and off the train by cranes and loaded off or onto trucks or ships. In the US, this type of freight train has largely superseded the traditional boxcar (wagon-load) type of freight train, which requires the cargo to be loaded or unloaded manually. In Europe the sliding wall wagon has taken over from the ordinary covered goods wagon.
In some countries "piggy-back" trains or rolling highways are used. In the latter case trucks can drive straight onto the train and drive off again when the end destination is reached. A system like this is used through the Channel Tunnel between England and France, and for the trans-Alpine service between France and Italy (this service uses Modalohr road trailer carriers). "Piggy-back" trains are the fastest growing type of freight train in the US, where they are also known as "trailer on flatcar" or TOFC trains. Piggy-back trains require no special modifications to the vehicles being carried. An alternative type of "intermodal" vehicle, known as a roadrailer, is designed to be physically attached to the train. The original trailers were fitted with two sets of wheels: one set flanged, for the trailer to run connected to other such trailers as a rail vehicle in a train; and one set with tires, for use as the semi-trailer of a road vehicle. More modern trailers have only road wheels and are designed to be carried on specially adapted bogies (trucks) when moving on rails.
There are also many other types of wagon, such as "low loader" wagons or well wagons for transporting road vehicles. There are refrigerator cars for transporting foods such as ice cream. There are simple types of open-topped wagons for transporting minerals and bulk material such as coal, and tankers for transporting liquids and gases. Today, however, most coal and aggregates are moved in hopper wagons that can be filled and discharged rapidly, to enable efficient handling of the materials.
Freight trains are sometimes illegally boarded by passengers who want a free ride, or do not have the money to travel by ordinary means.
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