Contents 1 History 1.1 Ancient systems 1.2 Pre-steam 1.2.1 Wooden rails introduced 1.2.2 Metal rails introduced 1.3 Steam power introduced 1.4 Electric power introduced 1.5 Diesel power introduced 1.6 High-speed rail 2 Trains 2.1 Haulage 2.2 Motive power 2.3 Passenger trains 2.4 Freight train 3 Infrastructure 3.1 Right of way 3.2 Trackage 3.3 Train inspection systems 3.4 Signalling 3.5 Electrification 3.6 Stations 4 Operations 4.1 Ownership 4.2 Financing 4.3 Safety 4.4 Maintenance 5 Social, economical, and energetic aspects 5.1 Energy 5.1.1 Energy efficiency 5.2 Usage 5.3 Social and economic benefits 5.4 Modern rail as economic development indicator 5.5 Subsidies 5.5.1 Asia 5.5.1.1 China 5.5.1.2 India 5.5.2 Europe 5.5.2.1 Russia 5.5.3 North America 5.5.3.1 United States 6 See also 7 References 8 Notes 9 External links

Social, economical, and energetic aspects Energy BNSF Railway freight service in the United States German InterCityExpress (ICE) Rail transport is an energy-efficient[66] but capital-intensive 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 being generated. Moving a vehicle on and/or through a medium (land, sea, or air) requires that it overcomes resistance to its motion caused by friction. A land vehicle's total resistance (in pounds or Newtons) is a quadratic function of the vehicle's speed: R = a + b v + c v 2 {\displaystyle \qquad \qquad R=a+bv+cv^{2}} where: R denotes total resistance a denotes initial constant resistance b denotes velocity-related constant c denotes constant that is function of shape, frontal area, and sides of vehicle v denotes velocity v2 denotes velocity, squared[56] Essentially, resistance differs between vehicle's contact point and surface of roadway. Metal wheels on metal rails have a significant advantage of overcoming resistance compared to rubber-tyred wheels on any road surface (railway – 0.001g at 10 miles per hour (16 km/h) and 0.024g at 60 miles per hour (97 km/h); truck – 0.009g at 10 miles per hour (16 km/h) and 0.090 at 60 miles per hour (97 km/h)). In terms of cargo capacity combining speed and size being moved in a day: human – can carry 100 pounds (45 kg) for 20 miles (32 km) per day, or 1 tmi/day (1.5 tkm/day) horse and wheelbarrow – can carry 4 tmi/day (5.8 tkm/day) horse cart on good pavement – can carry 10 tmi/day (14 tkm/day) fully utility truck – can carry 20,000 tmi/day (29,000 tkm/day)[citation needed] long-haul train – can carry 500,000 tmi/day (730,000 tkm/day)[56] Most trains take 250–400 trucks off the road, thus making the road more safe. In terms of the horsepower to weight ratio, a slow-moving barge requires 0.2 horsepower per short ton (0.16 kW/t), a railway and pipeline requires 2.5 horsepower per short ton (2.1 kW/t), and truck requires 10 horsepower per short ton (8.2 kW/t). However, at higher speeds, a railway overcomes the barge and proves most economical.[56] As an example, a typical modern wagon can hold up to 113 tonnes (125 short tons) of freight on two four-wheel bogies. The track distributes the weight of the train evenly, allowing significantly greater loads per axle and wheel than in road transport, leading to less wear and tear on the permanent way. This can save energy compared with other forms of transport, such as road transport, which depends on the friction between rubber tyres and the road. Trains have a small frontal area in relation to the load they are carrying, which reduces air 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 for economies of scale in both manpower and energy use; by contrast, in road transport, more than two articulations causes fishtailing and makes the vehicle unsafe. Energy efficiency Main article: Energy efficiency in transportation § Trains Considering only the energy spent to move the means of transport, and using the example of the urban area of Lisbon, 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.[67] 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 that one 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. Usage Due to these benefits, rail transport is a major form of passenger and freight transport in many countries. 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 the Northeast Corridor, due to increased preference of other modes, particularly automobiles and airplanes.[63][page needed][68] 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 the line to Lhasa, in Tibet,[69] 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. Social and economic benefits Japanese Shinkansen Railways are central to the formation of modernity and ideas of progress.[70] Railways contribute to social vibrancy and economic competitiveness by transporting multitudes of customers and workers to city centres and inner suburbs. Hong Kong has recognized rail as "the backbone of the public transit system" and as such developed their franchised bus system and road infrastructure in comprehensive alignment with their rail services.[71] China's large cities such as Beijing, Shanghai, and Guangzhou recognize rail transit lines as the framework and bus lines as the main body to their metropolitan transportation systems.[72] The Japanese Shinkansen was built to meet the growing traffic demand in the "heart of Japan's industry and economy" situated on the Tokyo-Kobe line.[73] German soldiers in a railway car on the way to the front in August 1914. The message on the car reads Von München über Metz nach Paris. (From Munich via Metz to Paris). During much of the 20th century, rail was an invaluable element of military mobilization, allowing for the quick and efficient transport of large numbers of reservists to their mustering-points, and infantry soldiers to the front lines. However, by the 21st century, rail transport – limited to locations on the same continent, and vulnerable to air attack – had largely been displaced by the adoption of aerial transport. Railways channel growth towards dense city agglomerations and along their arteries, as opposed to highway expansion, indicative of the U.S. transportation policy, which incents development of suburbs at the periphery, contributing to increased vehicle miles travelled, carbon emissions, development of greenfield spaces, and depletion of natural reserves. These arrangements revalue city spaces, local taxes,[74] housing values, and promotion of mixed use development.[75][76] Modern rail as economic development indicator European development economists have argued that the existence of modern rail infrastructure is a significant indicator of a country's economic advancement: this perspective is illustrated notably through the Basic Rail Transportation Infrastructure Index (known as BRTI Index).[77] Subsidies Main article: Rail subsidies Asia China In 2014, total rail spending by China was $130 billion and is likely to remain at a similar rate for the rest of the country's next Five Year Period (2016–2020).[78] India The Indian railways are subsidized by around ₹400 billion (US$6.1 billion), of which around 60% goes to commuter rail and short-haul trips.[79][80] It is the fourth largest railway network in the world comprising 119,630 kilometres (74,330 mi) of total track and 92,081 km (57,216 mi) of running track over a route of 66,687 km (41,437 mi) with 7,216 stations at the end of 2015-16. Europe For subsidies in Europe, see European rail subsidies European rail subsidies in euros per passenger-km for 2008[81] Country Subsidy in billions of Euros Year  Germany 17.0 2014[82]  France 13.2 2013[83]  Italy 8.1 2009[84]   Switzerland 5.8 2012[85]  Spain 5.1 2015[86]  United Kingdom 4.5 2015[87]  Belgium 3.4 2008[81]  Netherlands 2.5 2014[88]  Austria 2.3 2009[81]  Denmark 1.7 2008[81]  Sweden 1.6 2009[89]  Poland 1.4 2008[90]  Ireland 0.91 2008[90] Russia In total, Russian Roadways receives 90 billion roubles (around US$1,5 billion) annually from the government.[91] North America United States For rail subsidies in the United States, see Amtrak public funding and Modern US rail history Current subsidies for Amtrak (passenger rail) are around$1.4 billion.[92] The rail freight industry does not receive subsidies.

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Notes ^ According to this source, railways are the safest on both a per-mile and per-hour basis, whereas air transport is safe only on a per-mile basis