A train is a connected series of vehicles for rail transport that move along a track (permanent way) to transport freight or passengers from one place to another. The track usually consists of two rails, but might also be a monorail or maglev guideway.
Propulsion for the train is provided by a separate locomotive, or from individual motors in self-propelled multiple units. Most modern trains are powered by diesel locomotives or by electricity supplied by overhead wires or additional rails, although historically (from the early 19th century to the mid-20th century) the steam locomotive was the dominant form of locomotive power. Other sources of power (such as horses, rope or wire, gravity, pneumatics, and gas turbines) are possible.
The word 'train' comes from the Old French trahiner, itself from the Latin trahere 'pull, draw'.
There are various types of train designed for particular purposes. A train can consist of a combination of one or more locomotives and attached railroad cars, or a self-propelled multiple unit (or occasionally a single powered coach, called a railcar). Trains can also be hauled by horses, pulled by a cable, or run downhill by gravity.
Special kinds of trains running on corresponding special 'railways' are atmospheric railways, monorails, high-speed railways, maglev, rubber-tired underground, funicular and cog railways.
A passenger train may consist of one or several locomotives, and one or more coaches. Alternatively, a train may consist entirely of passenger carrying coaches, some or all of which are powered as a "multiple unit". In many parts of the world, particularly Japan and Europe, high-speed rail is utilized extensively for passenger travel.
Freight trains comprise wagons or trucks rather than carriages, though some parcel and mail trains (especially Travelling Post Offices) are outwardly more like passenger trains.
Trains can also be 'mixed', comprising both passenger accommodation and freight vehicles. Such mixed trains are most likely to occur where services are infrequent, and running separate passenger and freight trains is not cost-effective, though the differing needs of passengers and freight usually means this is avoided where possible.
Special trains are also used for track maintenance; in some places, this is called maintenance of way.
In the United Kingdom, a train hauled by two locomotives is said to be "double-headed", and in Canada and the United States it is quite common for a long freight train to be headed by three or more locomotives. A train with a locomotive attached at each end is described as 'top and tailed', this practice typically being used when there are no reversing facilities available. Where a second locomotive is attached temporarily to assist a train up steep banks or grades (or down them by providing braking power) it is referred to as 'banking' in the UK, or 'helper service' in North America. Recently, many loaded trains in the US have been made up with one or more locomotives in the middle or at the rear of the train, operated remotely from the lead cab. This is referred to as "DP" or "Distributed Power."
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.
In the United Kingdom Section 83(1) of the Railways Act 1993 defines "train" as follows:
a) two or more items of rolling stock coupled together, at least one of which is a locomotive; or
b) a locomotive not coupled to any other rolling stock.
In the United States, the term consist is used to describe the group of rail vehicles which make up a train. When referring to motive power, consist refers to the group of locomotives powering the train. Similarly, the term trainset refers 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).
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."
Main article: Bogie
A bogie (pronounced /ˈboʊɡi/, US dict: bō′·gē) 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.
Main article: Locomotive
The first trains were rope-hauled, gravity powered or pulled by horses. From the early 19th century almost all were powered by steam locomotives. From the 1910s onwards the steam locomotives began to be replaced by less labour intensive and cleaner (but more complex and expensive) diesel locomotives and electric locomotives, while at about the same time self-propelled multiple unit vehicles of either power system became much more common in passenger service. In most countries dieselisation of locomotives in day-to-day use was completed by the 1970s. A few countries, most notably the People's Republic of China, where coal and labour are cheap, still use a few steam locomotives, but most have been phased out. Historic steam trains still run in many other 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. Since the cost per mile of construction is much higher, electric traction is less viable for long-distance lines with the exception of long-distance high speed lines. Electric trains receive their current via overhead lines or through a third rail electric system.
A recent variation of the electric locomotive is the fuel cell locomotive. Fuel cell locomotives combine the advantage of not needing an electrical system in place, with the advantage of emissionless operation. However, the initial cost of such fuel cell vehicles is still substantial at the moment.
A passenger train is one which includes passenger-carrying vehicles. It may be a self-powered multiple unit or railcar, or else a combination of one or more locomotives and one or more unpowered trailers known as coaches, cars or carriages. Passenger trains travel between stations or depots, at which passengers may board and disembark. In most cases, passenger trains operate on a fixed schedule and have superior track occupancy rights over freight trains.
Oversight of a passenger train is the responsibility of the conductor. He or she is usually 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 distanced, 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. They often have a dining car or restaurant car to allow passengers to have a meal during the course of their journey. Trains travelling overnight may also have sleeping cars.
Main article: High-speed rail
One notable and growing long-distance train category is high-speed rail. Generally, high speed rail runs at speeds above 200 km/h (124 mph) and often operates on dedicated track that is surveyed and prepared to accommodate high speeds. Japan's Shinkansen ("bullet-train") commenced operation in 1964, and was the first successful example of a high speed passenger rail system.
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 (217 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 (186–199 mph), as does Germany's Inter-City Express.
In most cases, high-speed rail travel is time- and cost-competitive with air travel when distances do not exceed 500 to 600 km (311 to 373 mi), as airport check-in and boarding procedures may add as many as two hours to the actual 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, of course), as well as producing a more comfortable ride for passengers.
Main article: Maglev (transport)
In order to achieve much faster operation over 500 km/h (311 mph), innovative Maglev technology has been researched for years. 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 (267 mph). So far, however, Maglev has not been used for inter-city mass transit routes.
Main article: Inter-city rail
Passenger trains can be divided into three major groups:
Intercity trains: connecting cities in the fastest time possible, by passing all intermediate stations
Fast trains: calling at larger intermediate stations between cities, serving large urban communities
Regional trains: calling at all intermediate stations between cities, serving all lineside communities
The distinction between the types can be thin or even non-existent. Trains can run as Intercity services between major cities, then revert to a fast or even regional train service to serve communities at the extremity of their journey. This practice allows marginal communities remaining to be served while saving money at the expense of a longer journey time for those wishing to travel to the terminus station.
Main article: Regional rail
Regional trains usually connect between towns and cities, rather than purely linking major population hubs like inter-city train, and serve local traffic demand in relatively rural area.
Main articles: Commuter rail and Commuter rail in North America
For shorter distances many cities have networks of commuter trains, serving the city and its suburbs. Trains are a very efficient mode of transportation 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.
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. For example, an estimated 3.5 million passengers ride every day on Yamanote Line in Tokyo, Japan, with its 29 stations. For comparison, the New York City Subway carries 4.8 million passengers per day on 24 services serving 468 stations. To cope with large traffic, special cars in which the bench seats fold up to provide standing room only during the morning rush hour (until 10 a.m.) are operated in Tokyo (E231 series train). This train has as many as six sets of doors on each side to shorten the time for passengers to get on and off at station.
Passenger trains usually have emergency brake handles (or a "communication cord") that the public can operate. Misuse is punished by a heavy fine.
Main articles: Commuter rail in North America, Commuter rail, Rapid transit, and Urban rail in the United Kingdom
Large cities often have a metro system, also called underground, subway or tube. The trains are electrically powered, usually by third rail, and their railroads are separate from other traffic, usually without level crossings. Usually they run in tunnels in the city center and sometimes on elevated structures in the outer parts of the city. They can accelerate and decelerate faster than heavier, long-distance trains.
The term rapid transit is used for public transport such as commuter trains, metro and light rail. However, in New York City, services on the New York City Subway have been referred to as "trains".
Main article: Tram
In most countries, such as the United Kingdom, the distinction between a tramway and a railway is precise and defined in law. In the US and Canada such street railways are mostly referred to as trolleys. The key difference between a railroad and a trolley system is the latter running primarily on public streets, whereas trains have a right of way separated from the public. Often the US style interurban and modern light rail are confused with a trolley system, as it too may run on on the street for short or medium long sections. In some languages the word tram also refers to interurban and light rail -style networks, in particular Dutch.
The length of a tram or trolley may be determined by national regulations. Germany has the so-called Bo-Strab standard, restricting the length of a tram to 75 meters, while in the US, vehicle length is normally restricted by local authorities, often allowing only a single type of vehicle to operate on the network.
Main article: Light rail
The term light rail is sometimes used for a modern tram system, but it may also mean an intermediate form between a tram and a train, similar to a subway except that it may have level crossings. These are then usually protected with crossing gates. In US terminology these systems are often referred to as interurban, as they connect larger urban areas in the vicinity of a major city to that city. Modern light rail systems often use abandoned heavy rail rights of way (eg former railway lines) to revitalize deprived areas and redevelopment sites in and around large agglomerations.
Main article: Monorail
Monorail was developed to meet medium-demand traffic in urban transit, but represents a relatively small part of the overall railway field.
See also: Lists of named passenger trains
Railway companies often give a name to a train service as a marketing exercise, to raise the profile of the service and hence attract more passengers (and also to gain kudos for the company). Usually, naming is reserved for the most prestigious trains: the high-speed express trains between major cities, stopping at few intermediate stations. The names of services such as the Orient Express, the Flying Scotsman, the Flèche d'Or and the Royal Scot have passed into popular culture.
A somewhat less common practice is the naming of freight trains, for the same commercial reasons. The "Condor" was an overnight London-Glasgow express goods train, in the 1960s, hauled by pairs of "Metrovick" diesel locomotives. In the mid-1960s, British Rail introduced the "Freightliner" brand, for the new train services carrying containers between dedicated terminals around the rail network. The Rev. W. Awdry also named freight trains, coining the term The Flying Kipper for the overnight express fish train that appeared in his stories in The Railway Series books.
Main article: Heritage railway
Heritage trains are operated by volunteers, often railfans, as a tourist attraction. Usually trains are formed from historic vehicles retired from national commercial operation.
Airport trains transport people between terminals within an airport complex.
Mine trains are operated in large mines and carry both workers and goods.
Overland trains are used to carry cargo over rough terrain.
Main article: Freight rail transport
A freight train (also known as goods train) uses freight cars (also known as wagons or trucks) 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 in the United States the rail system is used more for transporting freight than passengers.
Under the right circumstances, transporting freight by train is highly economic, and also more energy efficient than transporting freight by road. Rail freight is most economic when freight is being carried in bulk and over long distances, but is less suited to short distances and small loads. Bulk aggregate movements of a mere twenty miles (32 km) can be cost effective even allowing for trans-shipment costs. These trans-shipment costs dominate in many cases and many modern practices such as Intermodal container freight are aimed at minimizing these.
The main disadvantage of rail freight is its lack of flexibility. For this reason, rail has lost much of the freight business to road competition. Many governments are now trying to encourage more freight onto trains, because of the benefits that it would bring.
There are many different types of freight trains, which are used to carry many different kinds of freight, with many different types of wagons. One of the most common types on modern railways are container trains, where containers can be lifted on and off the train by cranes and loaded off or onto trucks or ships.
In the U.S. this type of freight train has largely superseded the traditional boxcar (wagon-load) type of freight train, with which the cargo has 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 trains in the United States, 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 "inter-modal" 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 tyred, 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 wagons, such as "low loader" 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 do not wish to pay money, or do not have the money to travel by ordinary means. This is referred to as "freighthopping" and is considered by some communities to be a viable form of transport. A common way of boarding the train illegally is by sneaking into a train yard and stowing away in an unattended boxcar; a more dangerous practice is trying to catch a train "on the fly", that is, as it is moving, leading to occasional fatalities. Railroads treat it as trespassing and may prosecute it as such.