1.
103 series
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The 103 series is a commuter electric multiple unit type introduced in 1964 by Japanese National Railways, and currently operated by West Japan Railway Company and Kyushu Railway Company. They were also operated by East Japan Railway Company and Central Japan Railway Company, in 2004, some sets were shipped to Indonesia, where they operate on the KRL Jabodetabek system in Jakarta. The 103-0 series trains were built between 1963 and 1984 and this 8-car unit was built in 1963 without air-conditioning. The cars were withdrawn from service between 1988 and 1991, Moha 103, 901-902 Moha 102, 901-902 Kuha 103, 901-904 These were built between 1964 and 1970. While not originally fitted with air-conditioning, most of the cars were fitted with air conditioning from 1975, the bogies of the trailer cars were changed from TR201 to TR212 for the cars built from 1968. Cars fitted with TR212 bogies feature disc brakes, because they needed to run on higher speeds on the Jōban, KuMoHa 103, 1-155 MoHa 103, 1-278 MoHa 102, 1-433 KuHa 103, 1-177 & 501-638 SaHa 103, 1-305 This single 10-car unit was built in 1970. It was equipped with air conditioning units and tested on the Yamanote Line in Tokyo. It was subsequently modified to become a standard air-conditioned set in 1978, in 2000, four cars were scrapped at the Narashino Depot, the remaining six cars were scrapped at Keiyō Rolling Stock Center in 2005. MoHa 103, 279-281 MoHa 102, 434-436 KuHa 103, 178-179 SaHa 103, 306-307 Built during 1972 and 1973 and this type was used mainly in Osaka area. Most cars were fitted with air-conditioning from 1976, MoHa 103, 282-330 & 364-374 MoHa 102, 437-486 & 520-530 KuHa 103, 180-212 SaHa 103, 308-323 Built in 1973, they were similar to the air-conditioned prototype. They were fitted with motorized destination blinds on both sides, MoHa 103, 331-413 MoHa 102, 487-569 KuHa 103, 213-268 SaHa 103, 324-359 Built between 1974 and 1980. The front end design was changed with the drivers cab raised so that an ATC signalling system could be included, Kuha 103 of this version was used in the Tokyo area only. MoHa 103, 414-713 MoHa 102, 570-869 KuHa 103, 269-796,798,809,816 SaHa 103, the front end design was the same as the ATC-equipped sets, although this type was not fitted with ATC. Kuha 103-811 &816 were converted to include ATC in 1984, MoHa 103, 714-793 MoHa 102, 870-2050 KuHa 103,797, 799-850 SaHa 103, 472-503 Some 101 series trailer cars were converted to the 103-0 series. The cars bodies and bogies were 101 series originals as the conversions involved minimum modification, the last of these cars were withdrawn from service in 1999. SaHa 103, 751-780 KuHa 103, 2001-2004, 2051-2052160 103-1000 series cars were built in 1970 and 1971 for use on Jōban Line-Chiyoda Line inter-running services, originally painted in grey with a sea green stripe, they were subsequently displaced by new 203 series trains. Some sets were converted to become 105 series, and the rest of the fleet was reallocated to Jōban Line services from Ueno. The last set was retired in March 2006,5 sets were built between 1970 and 1978
2.
Japanese National Railways
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Japanese National Railways, abbreviated Kokutetsu or JNR, was the body which operated the national railway network of Japan from 1949 to 1987. As of June 1,1949, the date of establishment of JNR and this figure expanded to 21,421.1 km in 1981, but later reduced to 19,633.6 km as of March 31,1987, the last day of JNR. JNR operated both passenger and freight services, Shinkansen, the worlds first high-speed railway was debuted by JNR in 1964. Unlike railway operation, JNR Bus was not superior to local bus operators. The JR Bus companies are the successors of the bus operation of JNR, a number of unions represented workers at JNR, including the National Railway Workers Union, the National Railway Locomotive Engineers Union, and Doro-Chiba, a break-away group from Doro. Later, the Ministry of Railways and the Ministry of Transportation, the ministries used the name Japanese Government Railways to refer their network in English. During World War II, many JGR lines were dismantled to supply steel for the war effort, on June 1,1949 by a directive of the U. S. General HQ in Tokyo, JGR was reorganized into Japanese National Railways, JNR enjoyed many successes, including the October 1,1964 inauguration of high-speed Shinkansen service along the Tōkaidō Shinkansen line. However, JNR was not a corporation, its accounting was independent from the national budget. Rural sections without enough passengers began to press its management, pulling it further and further into debt, in 1983, JNR started to close its unprofitable 83 local lines. By 1987, JNRs debt was over ¥27 trillion and the company was spending ¥147 for every ¥100 earned. By an act of the Diet of Japan, on April 1,1987 JNR was privatized and divided into seven companies, six passenger and one freight. Long-term liabilities of JNR were taken over by the JNR Settlement Corporation and that corporation was subsequently disbanded on October 22,1998, and its remaining debts were transferred to the national budgets general accounting. By this time the debt has risen to ¥30 trillion, many lawsuits and labor commission cases were filed over the decades from the privatization in 1987. Kokuro and the National Railway Locomotive Engineers Union, both prominent Japanese railway unions, represented a number of the JNR workers, lists of workers to be employed by the new organizations were drawn up by JNR and given to the JR companies. There was substantial pressure on members to leave their unions, and within a year. Workers who had supported the privatization, or those who left Kokuro, were hired at substantially higher rates than Kokuro members. Around 7,600 workers were transferred in this way, and around 2,000 of them were hired by JR firms and this period ended in April 1990, and 1,047 were dismissed
3.
East Japan Railway Company
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East Japan Railway Company is a major passenger railway company in Japan and one of the seven Japan Railways Group companies. The company name is abbreviated as JR-EAST or JR East in English. The companys headquarters are in Yoyogi, Shibuya, Tokyo, JR East was incorporated on 1 April 1987 after being spun off from the government-run Japanese National Railways. Following the breakup, JR East ran the operations on former JNR lines in the Greater Tokyo Area, the Tohoku region and its railway lines primarily serve Kanto and Tohoku regions, along with adjacent areas in Koshinetsu region and Shizuoka prefectures. JR East operates all of the Shinkansen, high-speed rail lines and these lines have sections inside the Tokyo Suburban Area designated by JR East. This does not necessarily mean that the lines are fully inside the Greater Tokyo Area, JR East aims to reduce its carbon emissions by half, as measured over the period 1990-2030. This would be achieved by increasing the efficiency of trains and company-owned thermal power stations, the Tokyo Metropolitan Police Department has stated that JR Easts official union is a front for an organized crime syndicate called the Japan Revolutionary Communist League. An investigation of this is ongoing, the East Japan Railway Culture Foundation is a non-profit organization established by JR East for the purpose of developing a richer railway culture. The Railway Museum in Saitama is operated by the foundation, EJRC has bid for the London Midland franchise in the United Kingdom. Winners will be announced on June 2017 and will start operating on October 2017, East Japan Railway Company Web Site JR East official apology for Inaho No.14 accident on 25 December 2005 Company history books. Wiki collection of works on East Japan Railway Company
4.
Kisei Main Line
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The Kisei Main Line is a railway line that parallels the coastline of the Kii Peninsula in Japan between Mie Prefecture and Wakayama Prefecture. The name takes the characters from the names of the old provinces of Kii. The line is operated by Central Japan Railway Company from Kameyama, the terminus, to Shingū, and by West Japan Railway Company from Shingū to Wakayamashi. The segment between Shingū and Wakayama is nicknamed as the Kinokuni Line, after the name of the Kii Province. The line has connections with through service, to the Kansai Main Line for Nagoya via Ise Railway, the Kuroshio runs between Kyoto/Shin-Osaka/Tennōji and Shingū with 16 return workings a day. The line is divided to five parts for local services, by Shingū, Kii-Tanabe, Gobō. In 1891, the Kansai Railway opened the Kameyama to Tsu section, at the western end, the Kiwa Railway opened the Wakayamashi to Wakayama section in 1903, and was acquired by the Kansai Railway the following year. The Kansai Railway and the Sangu Railway were nationalised in 1907, in 1912, the Shingu Railway opened the Kii-Katsuura to Miwasaki section, extending the line to Shingu the following year. The company was nationalised in 1934, in 1935, the Kii-Katsuura to Taiji section was opened by JGR, extended to Kushimoto the following year, and to Esumi in 1940, providing a link to Wakayama and Osaka. The successor to JGR, the Japanese National Railways, opened the Owase to Shingu section in stages between 1956 and 1959, completing the line, the Akogi to Takajaya section was double-tracked in 1909, with the Matsusaka to Tokuwa section double-tracked two years later. In 1944, both sections were returned to track and the recovered materials recycled for the Japanese war effort. The Wakayama to Kii-Tanabe section was double-tracked in stages between 1964 and 1978, the line was electrified between Wakayama and Shingu in 1978, with the Wakayama to Wakayamashi section being commissioned in 1984. CTC signalling was commissioned between Wakayama and Shingu in 1978, and extended to Kameyama in 1983, Akogi Station, The Chusei Railway operated a 6 km 762 mm gauge line between Iwatahashi and Hisai between 1909 and 1942. At Hisai, it connected to the Dainippon Railway 15 km 762 mm gauge line to Ise-Kawaguchi on the Meisho Line between 1925 and 1942, Matsusaka Station, Mie Kotsu operated 20 km 762 mm line to Oishi between 1912 and 1964. The line was electrified at 600 V DC in 1927, although steam locomotives continued to be used until 1938, Tokuwa Station, The Ise Electric Railway main line connected here between 1930 and 1941. Funatsu Station, The Osugidani forest railway connected here to haul cedar and it was opened between 1929 and 1952 utilising 762 mm gauge, and featured a 17 km main line and nine branches of between 1 km and 11 km in length, as well as two cable-hauled inclines. The last line closed in 1974, fujinami Station, The 9 km Arita Railway line between Yuasa and Kanaya which operated between 1915 and 2003 connected at this station. Kainan Station, The Nogami Electric Railway operated an 11 km line, electrified at 600 V DC, freight services operated between 1951 and 1971
5.
Resistor
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A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses. High-power resistors that can dissipate many watts of power as heat may be used as part of motor controls, in power distribution systems. Fixed resistors have resistances that only slightly with temperature, time or operating voltage. Variable resistors can be used to adjust circuit elements, or as sensing devices for heat, light, humidity, force, Resistors are common elements of electrical networks and electronic circuits and are ubiquitous in electronic equipment. Practical resistors as discrete components can be composed of various compounds, Resistors are also implemented within integrated circuits. The electrical function of a resistor is specified by its resistance, the nominal value of the resistance falls within the manufacturing tolerance, indicated on the component. Two typical schematic diagram symbols are as follows, The notation to state a resistors value in a circuit diagram varies, one common scheme is the letter and digit code for resistance values following IEC60062. It avoids using a separator and replaces the decimal separator with a letter loosely associated with SI prefixes corresponding with the parts resistance. For example, 8K2 as part marking code, in a diagram or in a bill of materials indicates a resistor value of 8.2 kΩ. Additional zeros imply a tighter tolerance, for example 15M0 for three significant digits, when the value can be expressed without the need for a prefix, an R is used instead of the decimal separator. For example, 1R2 indicates 1.2 Ω, and 18R indicates 18 Ω, for example, if a 300 ohm resistor is attached across the terminals of a 12 volt battery, then a current of 12 /300 =0.04 amperes flows through that resistor. Practical resistors also have some inductance and capacitance which affect the relation between voltage and current in alternating current circuits, the ohm is the SI unit of electrical resistance, named after Georg Simon Ohm. An ohm is equivalent to a volt per ampere, since resistors are specified and manufactured over a very large range of values, the derived units of milliohm, kilohm, and megohm are also in common usage. The total resistance of resistors connected in series is the sum of their resistance values. R e q = R1 + R2 + ⋯ + R n, the total resistance of resistors connected in parallel is the reciprocal of the sum of the reciprocals of the individual resistors. 1 R e q =1 R1 +1 R2 + ⋯ +1 R n. For example, a 10 ohm resistor connected in parallel with a 5 ohm resistor, a resistor network that is a combination of parallel and series connections can be broken up into smaller parts that are either one or the other
6.
Railway electrification system
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A railway electrification system supplies electric power to railway trains and trams without an on-board prime mover or local fuel supply. Electrification has many advantages but requires significant capital expenditure, 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, Electric railways use electric locomotives to haul passengers or freight in separate cars or electric multiple units, passenger cars with their own motors. Electricity is typically generated in large and relatively efficient generating stations, transmitted to the railway network, 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 lines, switches and transformers. Power is supplied to moving trains with a continuous conductor running along the track usually takes one of two forms. The first is a line or catenary wire suspended from poles or towers along the track or from structure or tunnel ceilings. Locomotives or multiple units pick up power from the wire with pantographs on their roofs that press a conductive strip against it with a spring or air pressure. Examples are described later in this article, the second is a third rail mounted at track level and contacted by a sliding pickup shoe. Both overhead wire and third-rail systems usually use the rails as the return conductor. In comparison to the alternative, the diesel engine, electric railways offer substantially better energy efficiency, lower emissions. Electric locomotives are usually quieter, more powerful, and more responsive and they have no local emissions, an important advantage in tunnels and urban areas. Different regions may use different supply voltages and frequencies, complicating through service, the limited clearances available under catenaries may preclude efficient double-stack container service. Possible lethal electric current due to risk of contact with high-voltage contact wires, overhead wires are safer than third rails, but they are often considered unsightly. These are independent of the system used, so that. The permissible range of voltages allowed for the voltages is as stated in standards BS EN50163. These take into account the number of trains drawing current and their distance from the substation, railways must operate at variable speeds. Until the mid 1980s this was only practical with the brush-type DC motor, since such conversion was not well developed in the late 19th century and early 20th century, most early electrified railways used DC and many still do, particularly rapid transit and trams
7.
Current collector
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Those for overhead wires are roof-mounted devices, those for third rails are mounted on the bogies. Typically, they have one or more spring-loaded arms that permit the working engagement with the rail or overhead wire, the collector arm pushes the contact shoe against the contact wire or rail. As the vehicle moves, the shoe slides along the wire or rail to draw the electricity needed to run the vehicles motor. The current collector arms are electrically conductive but mounted insulated on the vehicles roof, an insulated cable connects the collector with the switch, transformer or motor. The steel rails of the act as the electrical return. Electric vehicles that collect their current from an overhead line system use different forms of one- or two-arm pantograph collectors, the current collection device presses against the underside of the lowest wire of an overhead line system, which is called a contact wire. Most overhead supply systems are either DC or single phase AC, three phase AC systems use a pair of overhead wires, and paired trolley poles. Electric railways with third rails, or fourth rails, in tunnels carry collector shoes projecting laterally, or vertically, the contact shoe may slide on top of the third rail, on the bottom or on the side. The side running contact shoe is used against the bars on rubber-tired metros. A vertical contact shoe is used on power supply systems, stud contact systems. A pair of shoes was used on underground current collection systems. The contact shoe on a contact system is called a ski collector. The ski collector moves vertically to accommodate variations in the height of the studs. Contact shoes may also be used on overhead conductor rails, on bars or on trolley wires. Most railways use three rails, while the London Underground uses four rails
8.
Railway brake
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Brakes are used on the cars of railway trains to enable deceleration, control acceleration or to keep them standing when parked. Clasp brakes are one type of historically used on trains. In the earliest days of railways, braking technology was primitive, some railways fitted a special deep-noted brake whistle to locomotives to indicate to the porters the necessity to apply the brakes. All the brakes at this stage of development were applied by operation of a screw and linkage to brake blocks applied to wheel treads, and it was also unreliable, as the application of brakes by guards depended upon them hearing and responding quickly to a whistle for brakes. This had become apparent from the trials on railway brakes carried out at Newark in the previous year, the chief types of solution were, The chain brake, such as the Heberlein brake, in which a chain was connected continuously along the train. As with car brakes, actuating pressure to apply brakes was transmitted hydraulically and these found some favor in the UK, but even in the UK problems were found with the water used as brake fluid freezing The Westinghouse air brake system. The Westinghouse system uses smaller air reservoirs and brake cylinders than the vacuum equipment. An ejector on the created a vacuum in a continuous pipe along the train. This system was very cheap and effective, but it had the weakness that it became inoperative if the train became divided or if the train pipe was ruptured. This system was similar to the vacuum system, except that the creation of vacuum in the train pipe exhausted vacuum reservoirs on every vehicle. If the driver applied the brake, his drivers brake valve admitted atmospheric air to the pipe. Being an automatic brake, this system applies braking effort if the train divided or if the train pipe is ruptured. Its disadvantage is that the vacuum reservoirs were required on every vehicle, and their bulk. Note, there are a number of variants and developments of all these systems, the Newark trials showed the braking performance of the Westinghouse air-brakes to be distinctly superior but for other reasons it was the vacuum system that was generally adopted on UK railways. Goods and mineral vehicles were provided with hand brakes by which the brakes could be applied by a lever operated by staff on the ground. Early goods vehicles had brake handles on one side only and random alignment of the vehicles gave the guard sufficient braking but, from about 1930 and these trains, not fitted with continuous brakes were described as unfitted trains and they survived in British practice until about 1985. By 1952 only 14% of open wagons, 55% of covered, in the early days of diesel locomotives, a purpose-built brake tender was attached to the locomotive to increase braking effort when hauling unfitted trains. The brake tender was low, so that the driver could see the line and signals ahead if the brake tender was propelled ahead of the locomotive
9.
Track gauge
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In rail transport, track gauge is the spacing of the rails on a railway track and is measured between the inner faces of the load-bearing rails. All vehicles on a network must have running gear that is compatible with the track gauge, as the dominant parameter determining interoperability, it is still frequently used as a descriptor of a route or network. There is a distinction between the gauge and actual gauge at some locality, due to divergence of track components from the nominal. Railway engineers use a device, like a caliper, to measure the actual gauge, the nominal track gauge is the distance between the inner faces of the rails. In current practice, it is specified at a distance below the rail head as the inner faces of the rail head are not necessarily vertical. In some cases in the earliest days of railways, the company saw itself as an infrastructure provider only. Colloquially the wagons might be referred to as four-foot gauge wagons, say and this nominal value does not equate to the flange spacing, as some freedom is allowed for. An infrastructure manager might specify new or replacement track components at a variation from the nominal gauge for pragmatic reasons. Track is defined in old Imperial units or in universally accepted metric units or SI units, Imperial units were established in United Kingdom by The Weights and Measures Act of 1824. In addition, there are constraints, such as the load-carrying capacity of axles. Narrow gauge railways usually cost less to build because they are lighter in construction, using smaller cars and locomotives, as well as smaller bridges, smaller tunnels. Narrow gauge is often used in mountainous terrain, where the savings in civil engineering work can be substantial. Broader gauge railways are generally expensive to build and require wider curves. There is no single perfect gauge, because different environments and economic considerations come into play, a narrow gauge is superior if ones main considerations are economy and tight curvature. For direct, unimpeded routes with high traffic, a broad gauge may be preferable, the Standard, Russian, and 46 gauges are designed to strike a reasonable balance between these factors. In addition to the general trade-off, another important factor is standardization, once a standard has been chosen, and equipment, infrastructure, and training calibrated to that standard, conversion becomes difficult and expensive. This also makes it easier to adopt an existing standard than to invent a new one and this is true of many technologies, including railroad gauges. The reduced cost, greater efficiency, and greater economic opportunity offered by the use of a common standard explains why a number of gauges predominate worldwide
10.
3 ft 6 in gauge railways
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Railways with a track gauge of 3 ft 6 in/1,067 mm were first constructed as horse-drawn wagonways. From the mid-nineteenth century, the 3 ft 6 in gauge became widespread in the British Empire, there are approximately 112,000 kilometres of 1,067 mm gauge track in the world. 1795 One of the first railways to use 3 ft 6 in gauge was the Little Eaton Gangway in England, other 3 ft 6 in gauge wagonways in England and Wales were also built in the early nineteenth century. 1862 In 1862 the Norwegian engineer Carl Abraham Pihl constructed the first 3 ft 6 in gauge railway in Norway,1865 In 1865 the Queensland Railways were constructed. Its 3 ft 6 in gauge was promoted by the Irish engineer Abraham Fitzgibbon,1868 In 1868 Charles Fox asks civil engineer Edmund Wragge to survey a 3 ft 6 in railway in Costa Rica. 1871 In 1871 the Canadian Toronto, Grey and Bruce Railway,1872 In January 1872 Robert Fairlie advocated the use of 3 ft 6 in gauge in his book Railways Or No Railways, Narrow Gauge, Economy with Efficiency v. Broad Gauge, Costliness with Extravagance. 1872 also saw the opening of the first 3 ft 6 in gauge railway in Japan,1873 On 1 January 1873, the first 3 ft 6 in gauge railway was opened in New Zealand, constructed by the British firm John Brogden and Sons. Earlier built 4 ft 8 1⁄2 in and broad gauge railways were converted to the narrower gauge. Also in 1873 the Cape Colony adopted the 3 ft 6 in gauge, after conducting several studies in southern Europe, the Molteno Government selected the gauge as being the most economically suited for traversing steep mountain ranges. Beginning in 1873, under supervision of Railway engineer of the Colony William Brounger, the Cape Government Railways rapidly expanded and the gauge became the standard for southern Africa. 1876 Natal also converted its short 10 kilometres long Durban network from 4 ft 8 1⁄2 in broad gauge prior to commencing with construction of a network across the colony in 1876. Other new railways in Southern Africa, notably Mozambique, Bechuanaland, after 1876 In the late nineteenth and early twentieth century numerous 3 ft 6 in gauge tram systems were built in the United Kingdom and the Netherlands. In Sweden, the gauge was nicknamed Blekinge gauge, as most of the railways in the province of Blekinge had this gauge. An alternate name for this gauge, Cape gauge, is named after the Cape Colony in what is now South Africa, the term Cape Gauge is used in other languages, such as the Dutch kaapspoor, German Kapspur, Norwegian kappspor and French voie cape. After metrication in the 1960s, the gauge was referred to in official South African Railways publications as 1065 mm instead of 1067 mm, the gauge is sometimes referred to as CAP gauge, after C. A. The gauge name Colonial Gauge was used in New Zealand, in Australia the imperial term 3 foot 6 inch is used. In some Australian publications the term medium gauge is also used, in Japan 1,067 mm gauge is referred to as kyōki, which directly translates as narrow gauge. It is defined in metric units, Cape Government Railways Heritage railway List of track gauges Norwegian gauge controversy South African Trains – A Pictorial Encyclopaedia Why Did Japan Choose the 36 Narrow Gauge
11.
Electric multiple unit
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An electric multiple unit or EMU is a multiple unit train consisting of self-propelled carriages, using electricity as the motive power. An EMU requires no separate locomotive, as traction motors are incorporated within one or a number of the carriages. An EMU is usually formed of two or more semi-permanently coupled carriages, but electrically powered single-unit railcars are also classed as EMUs. EMUs are popular on commuter and suburban rail networks around the world due to their fast acceleration, being quieter than DMUs and locomotive-drawn trains, EMUs can operate later at night and more frequently without disturbing residents living near the railway lines. The first EMUs were used on the elevated Liverpool Overhead Railway in 1893, the southern terminal of the railway was underground, giving the LOR the distinction of also being the first to use EMUs underground. Each carriage had a traction motor and was specifically designed and constructed to be light in weight while running on elevated steel sections. The first EMUs were two-carriage trains later graduating to three carriages, with the front and rear carriages powered, Liverpool Museum retains an example of the Liverpool Overhead Railway EMU carriage. An early proponent of EMUs was the American engineer Frank J. Sprague, the cars that form a complete EMU set can usually be separated by function into four types, power car, motor car, driving car, and trailer car. Each car can have more than one function, such as a car or power-driving car. A power car carries the equipment to draw power from the electrified infrastructure, such as pickup shoes for third rail systems and pantographs for overhead systems. Motor cars carry the traction motors to move the train, and are combined with the power car to avoid high-voltage inter-car connections. Driving cars are similar to a cab car, containing a drivers cab for controlling the train, an EMU will usually have two driving cars at its outer ends. Trailer cars are any cars that carry little or no traction or power related equipment, on third rail systems the outer vehicles usually carry the pick up shoes, with the motor vehicles receiving the current via intra-unit connections. Many modern 2-car EMU sets are set up as married pair units, while both units in a married pair are typically driving motors, the ancillary equipment are shared between the two cars in the set. Since neither car can operate without its partner, such sets are permanently coupled, advantages of married pair units include weight and cost savings over single-unit cars while allowing all cars to be powered, unlike a motor-trailer combination. Disadvantages include a loss of flexibility, as trains must be multiples of two cars, and a failure on a single car could force removing both it and its partner from service. The retired New York–Washington Metroliner service, first operated by the Pennsylvania Railroad and later by Amtrak, also featured high-speed electric multiple-unit cars, diesel multiple unit Battery electric multiple unit British electric multiple units Media related to Electric multiple unit at Wikimedia Commons
