Rolling stock on rails generally encounters lowerfrictional resistance than rubber-tyred road vehicles, allowing rail cars to be coupled into longertrains. Power is usually provided bydiesel orelectriclocomotives. While railway transport iscapital-intensive and less flexible than road transport, it can carry heavy loads of passengers and cargo with greater energy efficiency and safety.[a]
Precursors of railways driven by human or animal power have existed since antiquity, but modern rail transport began with the invention of thesteam locomotive in theUnited Kingdom at the beginning of the 19th century. The first passenger railway, theStockton and Darlington Railway, opened in 1825. The quick spread of railways throughout Europe and North America, following the1830 opening of the first intercity connection in England, was a key component of theIndustrial Revolution. The adoption of rail transport loweredshipping costs compared to water transport, leading to "national markets" in which prices varied less from city to city.[3]
Railroads not only increased the speed of transport, they also dramatically lowered its cost. For example, the first transcontinental railroad in the United States resulted in passengers and freight being able to cross the country in a matter of days instead of months and at one tenth the cost of stagecoach or wagon transport. With economical transportation in the West (which had been referred to as theGreat American Desert) now farming, ranching and mining could be done at a profit. As a result, railroads transformed the country, particularly the West (which had few navigable rivers).[4][5][6][7][8]
Smooth, durableroad surfaces have been made forwheeled vehicles since prehistoric times. In some cases, they were narrow and in pairs to support only the wheels. That is, they werewagonways or tracks. Some had grooves or flanges or other mechanical means to keep the wheels on track.
For example, evidence indicates that a 6 to 8.5 km longDiolkos paved trackway transported boats across theIsthmus of Corinth inGreece from around 600 BC. The Diolkos was in use for over 650 years, until at least the 1st century AD.[9] Paved trackways were also later built inRoman Egypt.[10]
A 16th-century mine-cart, an early example of un-powered rail transport, used man power to operate.
In 1515,Cardinal Matthäus Lang wrote a description of theReisszug, afunicular railway at theHohensalzburg Fortress in Austria. The line originally used wooden rails and ahemp haulage rope and was operated by human or animal power, through atreadwheel.[11] The line is still operational, although in updated form and is possibly the oldest operational railway.[12]
Wagonways (ortramways) using wooden rails, hauled by horses, started appearing in the 1550s to facilitate the transport of ore tubs to and from mines and soon became popular in Europe. Such an operation was illustrated inGermany in 1556 byGeorgius Agricola in his workDe re metallica.[13] This line used "Hund" carts with unflanged wheels running on wooden planks and a vertical pin on the truck fitting into the gap between the planks to keep it going the right way. The miners called the wagonsHunde ("dogs") from the noise they made on the tracks.[14]
There are many references to their use in central Europe in the 16th century.[15] Such a transport system was later used by German miners atCaldbeck,Cumbria, England, perhaps from the 1560s.[16] A wagonway was built atPrescot, nearLiverpool, sometime around 1600, possibly as early as 1594. Owned by Philip Layton, the line carried coal from a pit near Prescot Hall to a terminus about one-half mile (800 m) away.[17] A funicular railway was also made atBroseley inShropshire some time before 1604. This carried coal for James Clifford from his mines down to theRiver Severn to be loaded onto barges and carried to riverside towns.[18] TheWollaton Wagonway, completed in 1604 byHuntingdon Beaumont, has sometimes erroneously been cited as the earliest British railway. It ran fromStrelley toWollaton nearNottingham.[19]
TheMiddleton Railway inLeeds, which was built in 1758, later became the world's oldest operational railway (other than funiculars), albeit now in an upgraded form. In 1764, the first railway in the Americas was built inLewiston, New York.[20]
A replica of a "Little Eaton Tramway" wagon, 1795; the tracks are plateways.A cast iron fishbelly edge rail manufactured by Outram at the Butterley Company for theCromford and High Peak Railway in 1831; these are smooth edge rails for wheels with flanges.
In the late 1760s, theCoalbrookdale Company began to fix plates ofcast iron to the upper surface of the wooden rails. This allowed a variation ofgauge to be used. At first onlyballoon loops could be used for turning, but later, movable points were taken into use that allowed for switching.[21]
A system was introduced in which unflanged wheels ran on L-shaped metal plates, which came to be known asplateways.John Curr, aSheffield colliery manager, invented this flanged rail in 1787, though the exact date of this is disputed. The plate rail was taken up byBenjamin Outram for wagonways serving his canals, manufacturing them at hisButterley ironworks. In 1803,William Jessop opened theSurrey Iron Railway, a double track plateway, erroneously sometimes cited as world's first public railway, in south London.[22]
William Jessop had earlier used a form of all-ironedge rail and flanged wheels successfully for an extension to theCharnwood Forest Canal atNanpantan, Loughborough, Leicestershire in 1789. In 1790, Jessop and his partner Outram began to manufacture edge rails. Jessop became a partner in the Butterley Company in 1790. The first public edgeway (thus also first public railway) built wasLake Lock Rail Road in 1796. Although the primary purpose of the line was to carry coal, it also carried passengers.
These two systems of constructing iron railways, the "L" plate-rail and the smooth edge-rail, continued to exist side by side until well into the early 19th century. The flanged wheel and edge-rail eventually proved its superiority and became the standard for railways.
Cast iron used in rails proved unsatisfactory because it was brittle and broke under heavy loads. Thewrought iron invented byJohn Birkinshaw in 1820 replaced cast iron. Wrought iron, usually simply referred to as "iron", was a ductile material that could undergo considerable deformation before breaking, making it more suitable for iron rails. But iron was expensive to produce untilHenry Cort patented thepuddling process in 1784. In 1783 Cort also patented therolling process, which was 15 times faster at consolidating and shaping iron than hammering.[23] These processes greatly lowered the cost of producing iron and rails. The next important development in iron production washot blast developed byJames Beaumont Neilson (patented 1828), which considerably reduced the amount ofcoke (fuel) or charcoal needed to produce pig iron.[24] Wrought iron was a soft material that contained slag ordross. The softness and dross tended to make iron rails distort and delaminate and they lasted less than 10 years. Sometimes they lasted as little as one year under high traffic. All these developments in the production of iron eventually led to the replacement of composite wood/iron rails with superior all-iron rails.The introduction of theBessemer process, enabling steel to be made inexpensively, led to the era of great expansion of railways that began in the late 1860s. Steel rails lasted several times longer than iron.[25][26][27] Steel rails made heavier locomotives possible, allowing for longer trains and improving the productivity of railroads.[28] The Bessemer process introduced nitrogen into the steel, which caused the steel to become brittle with age. Theopen hearth furnace began to replace the Bessemer process near the end of the 19th century, improving the quality of steel and further reducing costs. Thus steel completely replaced the use of iron in rails, becoming standard for all railways.
The first passengerhorsecar ortram,Swansea and Mumbles Railway, was opened betweenSwansea andMumbles inWales in 1807.[29] Horses remained the preferable mode for tram transport even after the arrival of steam engines until the end of the 19th century, because they were cleaner compared to steam-driven trams which caused smoke in city streets.
In 1784,James Watt, a Scottish inventor and mechanical engineer, patented a design for asteam locomotive. Watt had improved thesteam engine ofThomas Newcomen, hitherto used to pump water out of mines, and developed areciprocating engine in 1769 capable of powering a wheel. This was a largestationary engine, powering cotton mills and a variety of machinery; the state of boiler technology necessitated the use of low-pressure steam acting upon a vacuum in the cylinder, which required a separatecondenser and anair pump. Nevertheless, as the construction of boilers improved, Watt investigated the use of high-pressure steam acting directly upon a piston, raising the possibility of a smaller engine that might be used to power a vehicle. Following his patent, Watt's employeeWilliam Murdoch produced a working model of a self-propelled steam carriage in that year.[30]
The first full-scale working railwaysteam locomotive was built in the United Kingdom in 1804 byRichard Trevithick, a British engineer born inCornwall. This used high-pressure steam to drive the engine by one power stroke. The transmission system employed a largeflywheel to even out the action of the piston rod. On 21 February 1804, the world's first steam-powered railway journey took place when Trevithick's unnamed steam locomotive hauled a train along the tramway of thePenydarren ironworks, near Merthyr Tydfil inSouth Wales.[31][32] Trevithick later demonstrated a locomotive operating upon a piece of circular rail track inBloomsbury, London, theCatch Me Who Can, but never got beyond the experimental stage with railway locomotives, not least because his engines were too heavy for the cast-iron plateway track then in use.[33]
The first commercially successful steam locomotive wasMatthew Murray'srack locomotiveSalamanca built for theMiddleton Railway inLeeds in 1812. This twin-cylinder locomotive was light enough to not break theedge-rails track and solved the problem ofadhesion by acog-wheel using teeth cast on the side of one of the rails. Thus it was also the firstrack railway.
This was followed in 1813 by the locomotivePuffing Billy built byChristopher Blackett andWilliam Hedley for theWylam Colliery Railway, the first successful locomotive running byadhesion only. This was accomplished by the distribution of weight between a number of wheels.Puffing Billy is now on display in theScience Museum in London, and is the oldest locomotive in existence.[34][35]
In 1814,George Stephenson, inspired by the early locomotives of Trevithick, Murray and Hedley, persuaded the manager of theKillingworthcolliery where he worked to allow him to build asteam-powered machine. Stephenson played a pivotal role in the development and widespread adoption of the steam locomotive. His designs considerably improved on the work of the earlier pioneers. He built the locomotiveBlücher, also a successfulflanged-wheel adhesion locomotive. In 1825 he built the locomotiveLocomotion for theStockton and Darlington Railway in the northeast of England, which became the first public steam railway in the world in 1825, although it used both horse power and steam power on different runs. In 1829, he built the locomotiveRocket, which entered in and won theRainhill Trials. This success led to Stephenson establishing his company as the pre-eminent builder of steam locomotives for railways in Great Britain and Ireland, the United States, and much of Europe.[36]: 24–30 The first public railway which used only steam locomotives, all the time, wasLiverpool and Manchester Railway, built in 1830.[37]
Steam power continued to be the dominant power system in railways around the world for more than a century.
The first known electric locomotive was built in 1837 by chemistRobert Davidson ofAberdeen in Scotland, and it was powered bygalvanic cells (batteries). Thus it was also the earliest battery-electric locomotive. Davidson later built a larger locomotive namedGalvani, exhibited at theRoyal Scottish Society of Arts Exhibition in 1841. The seven-ton vehicle had twodirect-drivereluctance motors, with fixed electromagnets acting on iron bars attached to a wooden cylinder on each axle, and simplecommutators. It hauled a load of six tons at four miles per hour (6 kilometers per hour) for a distance of one and a half miles (2.4 kilometres). It was tested on theEdinburgh and Glasgow Railway in September of the following year, but the limited power from batteries prevented its general use. It was destroyed by railway workers, who saw it as a threat to their job security.[38][39][40] By the middle of the nineteenth century most european countries had military uses for railways.[41]
The first use of electrification on a main line was on a four-mile section of theBaltimore Belt Line of theBaltimore and Ohio Railroad (B&O) in 1895 connecting the main portion of the B&O to the new line toNew York through a series of tunnels around the edges of Baltimore's downtown. Electricity quickly became the power supply of choice for subways, abetted by the Sprague's invention of multiple-unit train control in 1897. By the early 1900s most street railways were electrified.
Passengers waiting to board a tube train on theLondon Underground in the early 1900s (sketch by unknown artist)
The first practicalAC electric locomotive was designed byCharles Brown, then working forOerlikon, Zürich. In 1891, Brown had demonstrated long-distance power transmission, usingthree-phase AC, between ahydro-electric plant atLauffen am Neckar andFrankfurt am Main West, a distance of 280 km (170 mi). Using experience he had gained while working forJean Heilmann on steam–electric locomotive designs, Brown observed thatthree-phase motors had a higherpower-to-weight ratio thanDC motors and, because of the absence of acommutator, were simpler to manufacture and maintain.[b] However, they were much larger than the DC motors of the time and could not be mounted in underfloorbogies: they could only be carried within locomotive bodies.[45]
In 1894, Hungarian engineerKálmán Kandó developed a new type 3-phase asynchronous electric drive motors and generators for electric locomotives. Kandó's early 1894 designs were first applied in a short three-phase AC tramway inÉvian-les-Bains (France), which was constructed between 1896 and 1898.[46][47]
In 1896, Oerlikon installed the first commercial example of the system on theLugano Tramway. Each 30-tonne locomotive had two 110 kW (150 hp) motors run by three-phase 750 V 40 Hz fed from double overhead lines. Three-phase motors run at a constant speed and provideregenerative braking, and are well suited to steeply graded routes, and the first main-line three-phase locomotives were supplied by Brown (by then in partnership withWalter Boveri) in 1899 on the 40 kmBurgdorf–Thun line, Switzerland.
A prototype of a Ganz AC electric locomotive inValtellina, Italy, 1901
Italian railways were the first in the world to introduce electric traction for the entire length of a main line rather than a short section. The 106 kmValtellina line was opened on 4 September 1902, designed by Kandó and a team from the Ganz works.[48][49] The electrical system was three-phase at 3 kV 15 Hz. In 1918,[50] Kandó invented and developed therotary phase converter, enabling electric locomotives to use three-phase motors whilst supplied via a single overhead wire, carrying the simple industrial frequency (50 Hz) single phase AC of the high-voltage national networks.[49]
An important contribution to the wider adoption of AC traction came from SNCF of France after World War II. The company conducted trials at AC 50 Hz, and established it as a standard. Following SNCF's successful trials, 50 Hz, now also called industrial frequency was adopted as standard for main-lines across the world.[51]
Swiss &German co-production: world's first functional diesel–electric railcar 1914
Earliest recorded examples of aninternal combustion engine for railway use included a prototype designed byWilliam Dent Priestman.Sir William Thomson examined it in 1888 and described it as a "Priestman oil engine mounted upon a truck which is worked on a temporary line of rails to show the adaptation of a petroleum engine for locomotive purposes."[52][53] In 1894, a 20 hp (15 kW) two axle machine built byPriestman Brothers was used on theHull Docks.[54]
In 1906,Rudolf Diesel,Adolf Klose and the steam and diesel engine manufacturerGebrüder Sulzer founded Diesel-Sulzer-Klose GmbH to manufacture diesel-powered locomotives. Sulzer had been manufacturing diesel engines since 1898. The Prussian State Railways ordered a diesel locomotive from the company in 1909. The world's first diesel-powered locomotive was operated in the summer of 1912 on theWinterthur–Romanshorn railway in Switzerland, but was not a commercial success.[55] The locomotive weight was 95 tonnes and the power was 883 kW with a maximum speed of 100 km/h (62 mph).[56] Small numbers of prototype diesel locomotives were produced in a number of countries through the mid-1920s. TheSoviet Union operated three experimental units of different designs since late 1925, though only one of them (theE el-2) proved technically viable.[57]
A significant breakthrough occurred in 1914, whenHermann Lemp, aGeneral Electric electrical engineer, developed and patented a reliabledirect current electrical control system (subsequent improvements were also patented by Lemp).[58] Lemp's design used a single lever to control both engine and generator in a coordinated fashion, and was theprototype for alldiesel–electric locomotive control systems. In 1914, world's first functional diesel–electric railcars were produced for theKöniglich-Sächsische Staatseisenbahnen (Royal Saxon State Railways) byWaggonfabrik Rastatt with electric equipment fromBrown, Boveri & Cie and diesel engines fromSwissSulzer AG. They were classified asDET 1 and DET 2 (de.wiki). The first regular used diesel–electric locomotives wereswitcher (shunter) locomotives. General Electric produced several small switching locomotives in the 1930s (the famous "44-tonner" switcher was introduced in 1940) Westinghouse Electric and Baldwin collaborated to build switching locomotives starting in 1929.
In 1929, theCanadian National Railways became the first North American railway to use diesels in mainline service with two units, 9000 and 9001, from Westinghouse.[59]
Although steam and diesel services reaching speeds up to 200 km/h (120 mph) were started before the 1960s in Europe, they were not very successful.
0-SeriesShinkansen, introduced in 1964, triggered the intercity train travel boom.
The first electrifiedhigh-speed railTōkaidō Shinkansen was introduced in 1964 betweenTokyo andOsaka in Japan. Since thenhigh-speed rail transport, functioning at speeds up to and above 300 km/h (190 mph), has been built in Japan, Spain,France, Germany, Italy, the People's Republic of China,Taiwan (Republic of China), theUnited Kingdom,South Korea, Scandinavia, Belgium and the Netherlands. The construction of many of these lines has resulted in the dramatic decline of short-haul flights and automotive traffic between connected cities, such as the London–Paris–Brussels corridor, Madrid–Barcelona, Milan–Rome–Naples, as well as many other major lines.[citation needed]
Since 1980, rail transport has changed dramatically, but a number ofheritage railways continue to operate as part ofliving history to preserve and maintain old railway lines for services of tourist trains.
A train is a connected series of rail vehicles that move along the track. Propulsion for the train is provided by a separate locomotive or from individual motors in self-propelled multiple units. Most trains carry a revenue load, although non-revenue cars exist for the railway's own use, such as formaintenance-of-way purposes. Theengine driver (engineer in North America) controls the locomotive or other power cars, althoughpeople movers and some rapid transits are under automatic control.
Traditionally, trains are pulled using a locomotive. This involves one or more powered vehicles being located at the front of the train, providing sufficienttractive force to haul the weight of the full train. This arrangement remains dominant for freight trains and is often used for passenger trains. Apush–pull train has the end passenger car equipped with a driver's cab so that the engine driver can remotely control the locomotive. This allows one of the locomotive-hauled train's drawbacks to be removed, since the locomotive need not be moved to the front of the train each time the train changes direction. Arailroad car is a vehicle used for the haulage of either passengers or freight.
A multiple unit has powered wheels throughout the whole train. These are used for rapid transit and tram systems, as well as many both short- and long-haul passenger trains. Arailcar is a single, self-powered car, and may be electrically propelled or powered by adiesel engine. Multiple units have a driver's cab at each end of the unit, and were developed following the ability to buildelectric motors and other engines small enough to fit under the coach. There are only a few freight multiple units, most of which are high-speed post trains.
Steam locomotives are locomotives with asteam engine that provides adhesion.Coal,petroleum, orwood is burned in afirebox, boiling water in theboiler to create pressurized steam. The steam travels through thesmokebox before leaving via the chimney or smoke stack. In the process, it powers apiston that transmits power directly through aconnecting rod (US: main rod) and acrankpin (US: wristpin) on thedriving wheel (US main driver) or to acrank on a driving axle. Steam locomotives have been phased out in most parts of the world for economical and safety reasons, although many are preserved in working order byheritage railways.
Electric locomotives draw power from a stationary source via anoverhead wire orthird rail. Some also or instead use abattery. In locomotives that are powered by high-voltagealternating current, atransformer in the locomotive converts the high-voltage low-current power to low-voltage high current used in thetraction motors that power the wheels. Modern locomotives may usethree-phase AC induction motors ordirect current motors. Under certain conditions, electric locomotives are the most powerful traction.[citation needed] They are also the cheapest to run and provide less noise and no local air pollution.[citation needed] However, they require high capital investments both for theoverhead lines and the supporting infrastructure, as well as the generating station that is needed to produce electricity. Accordingly, electric traction is used on urban systems, lines with high traffic and for high-speed rail.
Diesel locomotives use a diesel engine as theprime mover. The energy transmission may be eitherdiesel–electric, diesel-mechanical or diesel–hydraulic but diesel–electric is dominant.Electro-diesel locomotives are built to run as diesel–electric on unelectrified sections and as electric locomotives on electrified sections.
Interior view of a high-speed bullet train, manufactured in China
A passenger train stops at stations where passengers may embark and disembark. The oversight of the train is the duty of aguard/train manager/conductor. Passenger trains are part of public transport and often make up the stem of the service, with buses feeding to stations. Passenger trains provide long-distance intercity travel, daily commuter trips, or local urban transit services, operating with a diversity of vehicles, operating speeds, right-of-way requirements, and service frequency. Service frequencies are often expressed as a number of trains per hour (tph).[60] Passenger trains can usually be into two types of operation, intercity railway and intracity transit. Whereas intercity railway involve higher speeds, longer routes, and lower frequency (usually scheduled), intracity transit involves lower speeds, shorter routes, and higher frequency (especially during peak hours).[61]
Intercity trains are long-haul trains that operate with few stops between cities. Trains typically have amenities such as adining car. Some lines also provide over-night services withsleeping cars. Some long-haul trains have been given aspecific name.Regional trains are medium distance trains that connect cities with outlying, surrounding areas, or provide a regional service, making more stops and having lower speeds.Commuter trains serve suburbs of urban areas, providing a dailycommuting service.Airport rail links provide quick access from city centres toairports.
High-speed rail are special inter-city trains that operate at much higher speeds than conventional railways, the limit being regarded at 200 to 350 kilometres per hour (120 to 220 mph). High-speed trains are used mostly for long-haul service and most systems are in Western Europe and East Asia.Magnetic levitation trains such as theShanghai maglev train use under-riding magnets which attract themselves upward towards the underside of a guideway and this line has achieved somewhat higher peak speeds in day-to-day operation than conventional high-speed railways, although only over short distances. Due to their heightened speeds, route alignments for high-speed rail tend to have broader curves than conventional railways, but may have steeper grades that are more easily climbed by trains with large kinetic energy.
Highkinetic energy translates to higher horsepower-to-ton ratios (e.g. 20 horsepower per short ton or 16 kilowatts per tonne); this allows trains to accelerate and maintain higher speeds and negotiate steep grades as momentum builds up and recovered in downgrades (reducingcut and fill and tunnelling requirements). Since lateral forces act on curves, curvatures are designed with the highest possible radius. All these features are dramatically different from freight operations, thus justifying exclusive high-speed rail lines if it is economically feasible.[61]
Higher-speed rail services are intercity rail services that have top speeds higher than conventional intercity trains but the speeds are not as high as those in the high-speed rail services. These services are provided after improvements to the conventional rail infrastructure to support trains that can operate safely at higher speeds.
Rapid transit is an intracity system built in large cities and has the highest capacity of any passenger transport system. It is usually grade-separated and commonly built underground or elevated. At street level, smallertrams can be used.Light rails are upgraded trams that have step-free access, their own right-of-way and sometimes sections underground.Monorail systems are elevated, medium-capacity systems. Apeople mover is a driverless, grade-separated train that serves only a few stations, as a shuttle. Due to the lack of uniformity of rapid transit systems, route alignment varies, with diverse rights-of-way (private land, side of road, street median) andgeometric characteristics (sharp or broad curves, steep or gentle grades). For instance, theChicago 'L' trains are designed with extremely short cars to negotiate the sharp curves in theLoop. New Jersey'sPATH has similar-sized cars to accommodate curves in the trans-Hudson tunnels. San Francisco'sBART operates large cars on its routes.[61]
Freight trains carrycargo usingfreight cars specialized for the type of goods. Freight trains are very efficient, with economy of scale and high energy efficiency.[62] However, their use can be reduced by lack of flexibility, if there is need of transshipment at both ends of the trip due to lack of tracks to the points of pick-up and delivery. Authorities often encourage the use of cargo rail transport due to its efficiency and to reduce road traffic.[63]
Container trains have become widely used in many places for general freight, particularly in North America, wheredouble stacking reduces costs. Containers can easily be transshipped between other modes, such as ships and trucks, and atbreaks of gauge. Containers have succeeded theboxcar (wagon-load), where the cargo had to be loaded and unloaded into the train manually. The intermodalcontainerization of cargo has revolutionized thesupply chainlogistics industry, reducing shipping costs significantly. In Europe, thesliding wall wagon has largely superseded theordinary covered wagons. Other types of cars includerefrigerator cars,stock cars for livestock andautoracks for road vehicles. When rail is combined with road transport, aroadrailer will allowtrailers to be driven onto the train, allowing for easy transition between road and rail.
Bulk handling represents a key advantage for rail transport. Low or even zero transshipment costs combined with energy efficiency and low inventory costs allow trains to handlebulk much cheaper than by road. Typical bulk cargo includes coal, ore, grains and liquids. Bulk is transported inopen-topped cars,hopper cars andtank cars.
Railway tracks are laid upon land owned or leased by the railway company. Owing to the desirability of maintaining modest grades, in hilly or mountainous terrain rails will often be laid in circuitous routes . Route length and grade requirements can be reduced by the use of alternatingcuttings, bridges and tunnels – all of which can greatly increase the capital expenditures required to develop a right-of-way, while significantly reducing operating costs and allowing higher speeds on longer radius curves. In densely urbanised areas, railways are sometimes laid in tunnels to minimise the effects on existing properties.
Track consists of two parallel steel rails, anchoredperpendicular to members calledsleepers (ties) of timber, concrete, steel, or plastic to maintain a consistent distance apart, orrail gauge. Other variations are also possible, such as "slab track", in which the rails are fastened to a concrete foundation resting on a prepared subsurface.
Rail gauges are usually categorized asstandard gauge (used on approximately 70% of the world's existing railway lines),broad gauge, andnarrow gauge.[64] In addition to the rail gauge, the tracks will be laid to conform with aloading gauge which defines the maximum height and width for railway vehicles and their loads to ensure safe passage through bridges, tunnels and other structures.
The track guides the conical, flanged wheels, keeping the cars on the track without active steering and therefore allowing trains to be much longer than road vehicles. The rails and ties are usually placed on a foundation made of compressed earth on top of which is placed a bed ofballast to distribute the load from the ties and to prevent the track frombuckling as the ground settles over time under the weight of the vehicles passing above.
The ballast also serves as a means of drainage. Some more modern track in special areas is attached directly without ballast. Track may be prefabricated or assembled in place. Bywelding rails together to form lengths ofcontinuous welded rail, additional wear and tear on rolling stock caused by the small surface gap at the joints between rails can be counteracted; this also makes for a quieter ride.
On curves, the outer rail may be at a higher level than the inner rail. This is called superelevation orcant. This reduces the forces tending to displace the track and makes for a more comfortable ride for standing livestock and standing or seated passengers. A given amount of superelevation is most effective over a limited range of speeds.
Points and switches – also known asturnouts – are the means of directing a train onto a diverging section of track. Laid similar to normal track, a point typically consists of afrog (common crossing), check rails and two switch rails. The switch rails may be moved left or right, under the control of the signalling system, to determine which path the train will follow.
Spikes in wooden ties can loosen over time, but split and rotten ties may be individually replaced with new wooden ties or concrete substitutes. Concrete ties can also develop cracks or splits, and can also be replaced individually. Should the rails settle due to soil subsidence, they can be lifted by specialized machinery and additional ballast tamped under the ties to level the rails.
Periodically, ballast must be removed and replaced with clean ballast to ensure adequate drainage. Culverts and other passages for water must be kept clear lest water is impounded by the trackbed, causing landslips. Where trackbeds are placed along rivers, additional protection is usually placed to prevent streambank erosion during times of high water. Bridges require inspection and maintenance, since they are subject to large surges of stress in a short period of time when a heavy train crosses.
The use of differenttrack gauges in different regions of the world, and sometimes within the same country, can impede the movement of passengers and freight. Often elaborate transfer mechanisms are installed where two lines of different gauge meet to facilitate movement across thebreak of gauge. Countries with multiple gauges in use, such asIndia andAustralia, have invested heavily to unify their rail networks. China is developing a modernizedEurasian Land Bridge to move goods by rail to Western Europe.
The inspection of railway equipment is essential for the safe movement of trains. Many types ofdefect detectors are in use on the world's railroads. These devices use technologies that vary from a simplistic paddle and switch toinfrared and laser scanning, and evenultrasonic audio analysis. Their use has avoided many rail accidents over the 70 years they have been used.
Bardon Hill box inEngland (seen here in 2009) is aMidland Railway box dating from 1899, although the original mechanical lever frame has been replaced by electrical switches.
Railway signalling is a system used to control railway traffic safely to prevent trains from colliding. Being guided by fixedrails which generate low friction, trains are uniquely susceptible to collision since they frequently operate at speeds that do not enable them to stop quickly or within the driver's sighting distance; road vehicles, which encounter a higher level of friction between their rubber tyres and the road surface, have much shorter braking distances. Most forms of train control involve movement authority being passed from those responsible for each section of a rail network to the train crew. Not all methods require the use of signals, and some systems are specific tosingle track railways.
The signalling process is traditionally carried out in asignal box, a small building that houses thelever frame required for the signalman to operate switches and signal equipment. These are placed at various intervals along the route of a railway, controlling specified sections of track. More recent technological developments have made such operational doctrine superfluous, with the centralization of signalling operations to regional control rooms. This has been facilitated by the increased use of computers, allowing vast sections of track to be monitored from a single location. The common method ofblock signalling divides the track into zones guarded by combinations of block signals, operating rules, and automatic-control devices so that only one train may be in a block at any time.
The electrification system provides electrical energy to the trains, so they can operate without a prime mover on board. This allows lower operating costs, but requires large capital investments along the lines. Mainline and tram systems normally have overhead wires, which hang from poles along the line. Grade-separated rapid transit sometimes use a groundthird rail.
Power may be fed asdirect (DC) oralternating current (AC). The most common DC voltages are 600 and 750 V for tram and rapid transit systems, and 1,500 and 3,000 V for mainlines. The two dominant AC systems are15 kV and25 kV.
Arailway station serves as an area where passengers can board and alight from trains. Agoods station is a yard which is exclusively used for loading and unloading cargo. Large passenger stations have at least one building providing conveniences for passengers, such as purchasing tickets and food. Smaller stations typically only consist of aplatform. Early stations were sometimes built with both passenger and goods facilities.[65]
Platforms are used to allow easy access to the trains, and are connected to each other viaunderpasses,footbridges andlevel crossings. Some large stations are built asculs-de-sac, with trains only operating out from one direction. Smaller stations normally serve local residential areas, and may have connection to feeder bus services. Large stations, in particularcentral stations, serve as the mainpublic transport hub for the city, and have transfer available between rail services, and to rapid transit, tram or bus services.
Since the 1980s, there has been an increasing trend to split up railway companies, with companies owning the rolling stock separated from those owning the infrastructure. This is particularly true in Europe, where this arrangement is required by the European Union. This has allowed open access by any train operator to any portion of the European railway network. In the UK, the railway track is state owned, with a public controlled body (Network Rail) running, maintaining and developing the track, while Train Operating Companies have run the trains sinceprivatization in the 1990s.[66]
In the U.S., virtually all rail networks and infrastructure outside theNortheast corridor are privately owned by freight lines. Passenger lines, primarilyAmtrak, operate as tenants on the freight lines. Consequently, operations must be closely synchronized and coordinated between freight and passenger railroads, with passenger trains often being dispatched by the host freight railroad. Due to this shared system, both are regulated by theFederal Railroad Administration (FRA) and may follow theAREMA recommended practices for track work andAAR standards for vehicles.[61]
The main source of income for railway companies is fromticket revenue (for passenger transport) and shipment fees for cargo.[67][68] Discounts and monthly passes are sometimes available for frequent travellers (e.g.season ticket andrail pass). Freight revenue may be sold per container slot or for a whole train. Sometimes, the shipper owns the cars and only rents the haulage. For passenger transport,advertisement income can be significant.
Governments may choose to give subsidies to rail operation, since rail transport has fewerexternalities than other dominant modes of transport. If the railway company is state-owned, the state may simply provide direct subsidies in exchange for increased production. If operations have been privatised, several options are available. Some countries have a system where the infrastructure is owned by a government agency or company – with open access to the tracks for any company that meets safety requirements. In such cases, the state may choose to provide the tracks free of charge, or for a fee that does not cover all costs. This is seen as analogous to the government providing free access to roads. For passenger operations, a direct subsidy may be paid to a public-owned operator, orpublic service obligation tender may be held, and a time-limited contract awarded to the lowest bidder.Total EU rail subsidies amounted to €73 billion in 2005.[69]
Via Rail Canada and US passenger rail serviceAmtrak are private railroad companies chartered by their respective national governments. As private passenger services declined because of competition from cars and airlines, they becameshareholders of Amtrak either with a cash entrance fee or relinquishing their locomotives and rolling stock. The government subsidises Amtrak by supplying start-upcapital and making up for losses at the end of thefiscal year.[70][page needed]
According toEurostat and theEuropean Railway Agency, the fatality risk for passengers and occupants on European railways is 28 times lower when compared with car usage (based on data by EU-27 member nations, 2008–2010).[71][72]
Some trains travel faster than road vehicles. They are heavy and unable to deviate from the track, and have longer stopping distances. Possible accidents includederailment (jumping the track) and collisions with another train or a road vehicle, or with pedestrians at level crossings, which account for the majority of all rail accidents and casualties. To minimize the risk, the most important safety measures are strict operating rules, e.g.railway signalling, and gates orgrade separation at crossings.Train whistles, bells, orhorns warn of the presence of a train, while trackside signals maintain the distances between trains. Another method used to increase safety is the addition ofplatform screen doors to separate the platform from train tracks. These prevent unauthorised incursion on to the train tracks which can result in accidents that cause serious harm or death, as well as providing other benefits such as preventing litter build up on the tracks which can pose a fire risk.
On many high-speed inter-city networks, such as Japan'sShinkansen, the trains run on dedicated railway lines without any level crossings. This is an important element in the safety of the system as it effectively eliminates the potential for collision with automobiles, other vehicles, or pedestrians, and greatly reduces the probability of collision with other trains. Another benefit is that services on the inter-city network remain punctual.
As in anyinfrastructure asset, railways must keep up with periodic inspection and maintenance to minimise the effect of infrastructure failures that can disrupt freight revenue operations and passenger services. Because passengers are considered the mostcrucial cargo and usually operate at higher speeds, steeper grades, and higher capacity/frequency, their lines are especially important. Inspection practices includetrack geometry cars or walking inspection. Curve maintenance especially for transit services includes gauging, fastener tightening, and rail replacement.
Rail corrugation is a common issue with transit systems due to the high number of light-axle, wheel passages which result in grinding of the wheel/rail interface. Since maintenance may overlap with operations, maintenance windows (nighttime hours,off-peak hours, altering train schedules or routes) must be closely followed. In addition, passenger safety during maintenance work (inter-track fencing, proper storage of materials, track work notices, hazards of equipment near states) must be regarded at all times. At times, maintenance access problems can emerge due to tunnels, elevated structures, and congested cityscapes. Here, specialised equipment or smaller versions of conventional maintenance gear are used.[61]
Unlikehighways orroad networks where capacity is disaggregated into unlinked trips over individual route segments, railway capacity is fundamentally considered a network system. As a result, many components are causes and effects of system disruptions. Maintenance must acknowledge the vast array of a route's performance (type of train service, origination/destination, seasonal impacts), a line's capacity (length, terrain, number of tracks, types of train control), trains throughput (max speeds, acceleration/ deceleration rates), and service features with shared passenger-freight tracks (sidings, terminal capacities, switching routes, and design type).[61]
Transport by rail is anenergy-efficient[73] butcapital-intensive[74] means of mechanized land transport. The tracks provide smooth and hard surfaces on which the wheels of the train can roll with a relatively low level of friction.
A typical modern wagon can hold up to 113 tonnes (125 short tons) of freight on two four-wheelbogies. The track distributes the weight of the train evenly, allowing significantly greater loads peraxle and wheel than in road transport, leading to greater energy efficiency. Trains have a smaller frontal area in relation to the load they are carrying, which reducesair resistance and thus energy usage.
In addition, the presence of track guiding the wheels allows for very long trains to be pulled by one or a few engines and driven by a single operator, even around curves, which allows foreconomies of scale in both manpower and energy use; by contrast, in road transport, more than twoarticulations causesfishtailing and makes the vehicle unsafe.
Considering only the energy spent to move the means of transport, and using the example of the urban area ofLisbon, electric trains seem to be on average 20 times more efficient than automobiles for transportation of passengers, if we consider energy spent per passenger-distance with similar occupation ratios.[75] Considering an automobile with a consumption of around 6 L/100 km (47 mpg‑imp; 39 mpg‑US) of fuel, the average car in Europe has an occupancy of around 1.2 passengers per automobile (occupation ratio around 24%) and thatone litre of fuel amounts to about 8.8 kWh (32 MJ), equating to an average of 441 Wh (1,590 kJ) per passenger-km. This compares to a modern train with an average occupancy of 20% and a consumption of about 8.5 kW⋅h/km (31 MJ/km; 13.7 kW⋅h/mi), equating to 21.5 Wh (77 kJ) per passenger-km, 20 times less than the automobile.
Due to these benefits, rail transport is a major form of passenger and freight transport in many countries.[74] It is ubiquitous in Europe, with an integrated network covering virtually the whole continent. In India, China, South Korea and Japan, many millions use trains as regular transport. In North America, freight rail transport is widespread and heavily used, but intercity passenger rail transport is relatively scarce outside theNortheast Corridor, due to increased preference of other modes, particularly automobiles and airplanes.[70][page needed][76] However, implementing new and improved ways such as making it easily accessible within neighborhoods can aid in reducing commuters from using private vehicles and airplanes.[77]
South Africa, northern Africa and Argentina have extensive rail networks, but some railways elsewhere in Africa and South America are isolated lines. Australia has a generally sparse network befitting its population density but has some areas with significant networks, especially in the southeast. In addition to the previously existing east–west transcontinental line in Australia, a line from north to south has been constructed. The highest railway in the world is theline to Lhasa, in Tibet,[78] partly running over permafrost territory. Western Europe has the highest railway density in the world and many individual trains there operate through several countries despite technical and organizational differences in each national network.
Historically, railways have been considered central to modernity and ideas of progress.[79] The process of modernization in the 19th century involved a transition from a spatially oriented world to a time-oriented world. Timekeeping became of heightened importance, resulting in clock towers for railway stations, clocks in public places, and pocket watches for railway workers and travellers. Trains followed exact schedules and never left early, whereas in the premodern era, passenger ships left whenever the captain had enough passengers. In the premodern era, local time was set at noon, when the sun was at its highest; this changed with the introduction of standardtime zones. Printed timetables were a convenience for travellers, but more elaborate timetables, calledtrain orders, were essential for train crews, the maintenance workers, the station personnel, and for the repair and maintenance crews. The structure of railway timetables were later adapted for different uses, such as schedules for buses, ferries, and airplanes, for radio and television programmes, for school schedules, and for factory time clocks.[80]
The invention of theelectrical telegraph in the early 19th century also was crucial for the development and operation of railroad networks. If bad weather disrupted the system, telegraphers relayed immediate corrections and updates throughout the system. Additionally, most railroads were single-track, withsidings and signals to allow lower priority trains to be sidetracked and have scheduled meets.
According to historianHenry Adams, a railroad network needed:
the energies of a generation, for it required all the new machinery to be created – capital, banks, mines, furnaces, shops, power-houses, technical knowledge, mechanical population, together with a steady remodelling of social and political habits, ideas, and institutions to fit the new scale and suit the new conditions. The generation between 1865 and 1895 was already mortgaged to the railways, and no one knew it better than the generation itself.[82]
The impact can be examined through five aspects: shipping, finance, management, careers, and popular reaction.
Railroads form an efficient network for shipping freight and passengers across a large national market; their development thus was beneficial to many aspects of a nation's economy, including manufacturing, retail and wholesale, agriculture, and finance. By the 1940s, the United States had an integrated national market comparable in size to that of Europe, but free of internal barriers or tariffs, and supported by a common language, financial system, and legal system.[83]
Financing of railroads provided the basis for a dramatic expansion of the private (non-governmental)financial system. Construction of railroads was far more expensive than factories: in 1860, the combined total of railroad stocks and bonds was $1.8 billion; in 1897, it reached $10.6 billion (compared to a total national debt of $1.2 billion).[84]
Funding came from financiers in theNortheastern United States and from Europe, especially Britain.[85] About 10 percent of the funding came from the government, particularly in the form of land grants that were realized upon completion of a certain amount of trackage.[86] The emerging American financial system was based on railroad bonds, and by 1860, New York was the dominant financial market. The British invested heavily in railroads around the world, but nowhere more than in the United States; the total bond value reached about $3 billion by 1914. However, in 1914–1917, the British liquidated their American assets to pay for war supplies.[87][88]
Railroad management designed complex systems that could handle far more complicated simultaneous relationships than those common in other industries at the time. Civil engineers became the senior management of railroads. The leading American innovators were theWestern Railroad of Massachusetts and theBaltimore and Ohio Railroad in the 1840s, theErie Railroad in the 1850s, and thePennsylvania Railroad in the 1860s.[89]
The development of railroads led to the emergence of private-sector careers for both blue-collar workers and white-collar workers. Railroading became a lifetime career for young men; women were almost never hired. A typical career path would see a young man hired at age 18 as a shop labourer, be promoted to skilled mechanic at age 24, brakemen at 25, freight conductor at 27, and passenger conductor at age 57. White-collar career paths likewise were delineated: educated young men started in clerical or statistical work and moved up to station agents or bureaucrats at the divisional or central headquarters, acquiring additional knowledge, experience, andhuman capital at each level. Being very hard to replace, they were virtually guaranteed permanent jobs and provided with insurance and medical care.
Hiring, firing, and wage rates were set not by foremen, but by central administrators, to minimize favouritism and personality conflicts. Everything was done by the book, whereby an increasingly complex set of rules dictated to everyone exactly what should be done in every circumstance, and exactly what their rank and pay would be. By the 1880s, career railroaders began retiring, and pension systems were invented for them.[90]
Railways contribute to social vibrancy and economic competitiveness by transporting multitudes of customers and workers tocity centres andinner suburbs.Hong Kong has recognized rail as "the backbone of thepublic transit system" and as such developed their franchised bus system and road infrastructure in comprehensive alignment with their rail services.[91] China's large cities such asBeijing,Shanghai, andGuangzhou recognize rail transit lines as the framework and bus lines as the main body to their metropolitan transportation systems.[92] The JapaneseShinkansen was built to meet the growing traffic demand in the "heart of Japan's industry and economy" situated on theTokyo-Kobe line.[93]
German soldiers in a railwaycar on the way to the front in August 1914. The message on the car readsVon München über Metz nach Paris ("From Munich via Metz to Paris").
Rail transport can be important for military activity. During the 1860s, railways provided a means for rapid movement of troops and supplies during theAmerican Civil War,[94] as well as in theAustro-Prussian andFranco-Prussian Wars[95] Throughout the 20th century, rail was a key element of war plans for rapid militarymobilization, allowing for the quick and efficient transport of large numbers of reservists to their mustering-points, and infantry soldiers to the front lines.[96] So-calledstrategic railways were or are constructed for a primarily military purpose. The Western Front in France duringWorld War I required many trainloads of munitions a day.[97] Conversely, owing to their strategic value, rail yards and bridges in Germany and occupied France were major targets of Allied air raids during World War II.[98] Rail transport and infrastructure continues to play an important role in present-day conflicts like theRussian invasion of Ukraine, wheresabotage of railways in Belarus andin Russia also influenced the course of the war.
There has also been some opposition to the development of railway networks. For instance, the arrival of railways andsteam locomotives to Austria during the 1840s angered locals because of the noise, smell, and pollution caused by the trains and the damage to homes and the surrounding land caused by the engine's soot and fiery embers; and since most travel did not occur over long distances, few people utilized the new line.[102]
A 2018 study found that the opening of theBeijing Metro caused a reduction in "most of the air pollutants concentrations (PM2.5, PM10, SO2, NO2, and CO) but had little effect on ozone pollution."[103]
In 2010, annual rail spending in China was ¥840 billion (US$173 billion in 2023), from 2014 to 2017 China had an annual target of ¥800 billion (US$164 billion in 2023) and planned to spend ¥3.5 trillion (US$30 trillion in 2023) over 2016–2020.[105]
TheIndian Railways are subsidized by around ₹260 billion (US$5 billion in 2023), of which around 60% goes to commuter rail and short-haul trips.[106]
European rail subsidies in euros per passenger-km for 2008[107]
According to the 2017 European Railway Performance Index for intensity of use, quality of service and safety performance, the top tier European national rail systems consists of Switzerland, Denmark, Finland, Germany, Austria, Sweden, and France.[108] Performance levels reveal a positive correlation between public cost and a given railway system's performance, and also reveal differences in the value that countries receive in return for their public cost. Denmark, Finland, France, Germany, the Netherlands, Sweden, and Switzerland capture relatively high value for their money, while Luxembourg, Belgium, Latvia, Slovakia, Portugal, Romania, and Bulgaria underperform relative to the average ratio of performance to cost among European countries.[108]
In 2015, funding from theU.S. federal government forAmtrak was around US$1.4 billion.[119] By 2018, appropriated funding had increased to approximately US$1.9 billion.[120]
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