Railway electrification is the use of electric power for the propulsion of rail transport. Electric railways use either electric locomotives (hauling passengers or freight in separate cars), electric multiple units (passenger cars with their own motors) or both.Electricity is typically generated in large and relatively efficient generating stations, transmitted to the railway network and distributed to the trains. Some electric railways have their own dedicated generating stations and transmission lines, but most purchase power from an electric utility. The railway usually provides its own distribution lines, switches, and transformers.
Power is supplied to moving trains with a (nearly) continuous conductor running along the track that usually takes one of two forms: an overhead line, suspended from poles or towers along the track or from structure or tunnel ceilings, or a third rail mounted at track level and contacted by a sliding "pickup shoe". Both overhead wire and third-rail systems usually use the running rails as the return conductor, but some systems use a separate fourth rail for this purpose.
Electric Train Indian Rail Road Game Download
Download 🔥 https://tiurll.com/2yGAvL 🔥
In comparison to the principal alternative, the diesel engine, electric railways offer substantially better energy efficiency, lower emissions, and lower operating costs. Electric locomotives are also usually quieter, more powerful, and more responsive and reliable than diesel. They have no local emissions, an important advantage in tunnels and urban areas. Some electric traction systems provide regenerative braking that turns the train's kinetic energy back into electricity and returns it to the supply system to be used by other trains or the general utility grid. While diesel locomotives burn petroleum products, electricity can be generated from diverse sources, including renewable energy.[1] Historically, concerns of resource independence have played a role in the decision to electrify railway lines. The landlocked Swiss confederation which almost completely lacks oil or coal deposits but has plentiful hydropower electrified its network in part in reaction to supply issues during both World Wars.[2][3]
Disadvantages of electric traction include: high capital costs that may be uneconomic on lightly trafficked routes, a relative lack of flexibility (since electric trains need third rails or overhead wires), and a vulnerability to power interruptions.[1] Electro-diesel locomotives and electro-diesel multiple units mitigate these problems somewhat as they are capable of running on diesel power during an outage or on non-electrified routes.
Different regions may use different supply voltages and frequencies, complicating through service and requiring greater complexity of locomotive power. There used to be a historical concern for double-stack rail transport regarding clearances with overhead lines[1] but it is no longer universally true as of 2022[update], with both Indian Railways[4] and China Railway[5][6][7] regularly operating electric double-stack cargo trains under overhead lines.
Railway electrification has constantly increased in the past decades, and as of 2022, electrified tracks account for nearly one-third of total tracks globally.[8][9] Electrification projects are constantly undertaken to service rapidly growing suburbs formerly served by non-electrified trains which typically have low capacities.
Railway electrification is the development of powering trains and locomotives using electricity instead of diesel or steam power. The history of railway electrification dates back to the late 19th century when the first electric tramways were introduced in cities like Berlin, London, and New York City.
The early electrification of railways used direct current (DC) power systems, which were limited in terms of the distance they could transmit power. However, in the early 20th century, alternating current (AC) power systems were developed, which allowed for more efficient power transmission over longer distances.
In the 1920s and 1930s, many countries worldwide began to electrify their railways. In Europe, Switzerland, Sweden, France, and Italy were among the early adopters of railway electrification. In the United States, the New York, New Haven and Hartford Railroad was one of the first major railways to be electrified.
Railway electrification continued to expand throughout the 20th century, with technological improvements and the development of high-speed trains and commuters. Today, many countries have extensive electrified railway networks with 375000 km of standard lines in the world, including China, India, Japan, France, Germany, and the United Kingdom. Electrification is seen as a more sustainable and environmentally friendly alternative to diesel or steam power and is an important part of many countries' transportation infrastructure.
Selection of an electrification system is based on economics of energy supply, maintenance, and capital cost compared to the revenue obtained for freight and passenger traffic. Different systems are used for urban and intercity areas; some electric locomotives can switch to different supply voltages to allow flexibility in operation.
Six of the most commonly used voltages have been selected for European and international standardisation. Some of these are independent of the contact system used, so that, for example, 750 V DC may be used with either third rail or overhead lines.
There are many other voltage systems used for railway electrification systems around the world, and the list of railway electrification systems covers both standard voltage and non-standard voltage systems.
The permissible range of voltages allowed for the standardised voltages is as stated in standards BS EN 50163[10] and IEC 60850.[11] These take into account the number of trains drawing current and their distance from the substation.
In the United Kingdom, 1,500 V DC was used in 1954 for the Woodhead trans-Pennine route (now closed); the system used regenerative braking, allowing for transfer of energy between climbing and descending trains on the steep approaches to the tunnel. The system was also used for suburban electrification in East London and Manchester, now converted to 25 kV AC. It is now only used for the Tyne and Wear Metro. In India, 1,500 V DC was the first electrification system launched in 1925 in Mumbai area. Between 2012 and 2016, the electrification was converted to 25 kV 50 Hz, which is the countrywide system.
3 kV DC is used in Belgium, Italy, Spain, Poland, Slovakia, Slovenia, South Africa, Chile, the northern portion of the Czech Republic, the former republics of the Soviet Union, and in the Netherlands on a few kilometers between Maastricht and Belgium. It was formerly used by the Milwaukee Road from Harlowton, Montana, to Seattle, across the Continental Divide and including extensive branch and loop lines in Montana, and by the Delaware, Lackawanna and Western Railroad (now New Jersey Transit, converted to 25 kV AC) in the United States, and the Kolkata suburban railway (Bardhaman Main Line) in India, before it was converted to 25 kV 50 Hz.
DC voltages between 600 V and 750 V are used by most tramways and trolleybus networks, as well as some metro systems as the traction motors accept this voltage without the weight of an on-board transformer.[citation needed]
In the 1960s the Soviets experimented with boosting the overhead voltage from 3 to 6 kV. DC rolling stock was equipped with ignitron-based converters to lower the supply voltage to 3 kV. The converters turned out to be unreliable and the experiment was curtailed. In 1970 the Ural Electromechanical Institute of Railway Engineers carried out calculations for railway electrificationat 12 kV DC, showing that the equivalent loss levels for a 25 kV AC system could be achieved with DC voltage between 11 and 16 kV. In the 1980s and 1990s 12 kV DC was being tested on the October Railway near Leningrad (now Petersburg). The experiments ended in 1995 due to the end of funding.[15]
Most electrification systems use overhead wires, but third rail is an option up to 1,500 V. Third rail systems almost exclusively use DC distribution. The use of AC is usually not feasible due to the dimensions of a third rail being physically very large compared with the skin depth that AC penetrates to 0.3 millimetres or 0.012 inches in a steel rail. This effect makes the resistance per unit length unacceptably high compared with the use of DC.[16] Third rail is more compact than overhead wires and can be used in smaller-diameter tunnels, an important factor for subway systems.[citation needed]
The key advantage of the four-rail system is that neither running rail carries any current. This scheme was introduced because of the problems of return currents, intended to be carried by the earthed (grounded) running rail, flowing through the iron tunnel linings instead. This can cause electrolytic damage and even arcing if the tunnel segments are not electrically bonded together. The problem was exacerbated because the return current also had a tendency to flow through nearby iron pipes forming the water and gas mains. Some of these, particularly Victorian mains that predated London's underground railways, were not constructed to carry currents and had no adequate electrical bonding between pipe segments. The four-rail system solves the problem. Although the supply has an artificially created earth point, this connection is derived by using resistors which ensures that stray earth currents are kept to manageable levels. Power-only rails can be mounted on strongly insulating ceramic chairs to minimise current leak, but this is not possible for running rails, which have to be seated on stronger metal chairs to carry the weight of trains. However, elastomeric rubber pads placed between the rails and chairs can now solve part of the problem by insulating the running rails from the current return should there be a leakage through the running rails.
The Expo and Millennium Line of the Vancouver SkyTrain use side-contact fourth-rail systems for their 650 V DC supply. Both are located to the side of the train, as the space between the running rails is occupied by an aluminum plate, as part of stator of the linear induction propulsion system used on the Innovia ART system. While part of the SkyTrain network, the Canada Line does not use this system and instead uses more traditional motors attached to the wheels and third-rail electrification. 152ee80cbc
sura yasin bangla ortho soho mp3 download