1.
Trolleybus
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A trolleybus is an electric bus that draws power from overhead wires using spring-loaded trolley poles. Two wires and poles are required to complete the electrical circuit and this differs from a tram or streetcar, which normally uses the track as the return path, needing only one wire and one pole. They are also distinct from other kinds of buses, which usually rely on batteries. Power is most commonly supplied as 600-volt direct current, but there have been, currently, around 300 trolleybus systems are in operation, in cities and towns in 43 countries. Altogether, more than 800 trolleybus systems have existed, but not more than about 400 concurrently, the trolleybus dates back to 29 April 1882, when Dr. Ernst Werner Siemens demonstrated his Elektromote in a Berlin suburb. This experiment continued until 13 June 1882, after there were few developments in Europe. In 1899, another vehicle which could run either on or off rails was demonstrated in Berlin, routes followed in Eberswalde and Fontainebleau. Max Schiemann on 10 July 1901 opened the worlds fourth passenger-carrying trolleybus system, although this system operated only until 1904, Schiemann had developed what is now the standard trolleybus current collection system. In the early days there were a few methods of current collection. The Cédès-Stoll system was operated near Dresden between 1902 and 1904, and in Vienna, the Lloyd-Köhler or Bremen system was tried out in Bremen, and the Cantono Frigerio system was demonstrated near Milan. Throughout the period, trackless freight systems and electric canal boats were also built, Leeds and Bradford became the first cities to put trolleybuses into service in Great Britain on 20 June 1911. Apparently, though it was opened on 20 June, the public was not admitted to the Bradford route until the 24th, Bradford was also the last to operate trolleybuses in the UK, the system closing on 26 March 1972. The last rear-entrance trolleybus in Britain was also in Bradford and is now owned by the Bradford Trolleybus Association, birmingham was the first to replace a tram route with trolleybuses, while Wolverhampton, under the direction of Charles Owen Silvers, became world-famous for its trolleybus designs. There were 50 trolleybus systems in the UK, Londons being the largest, by the time trolleybuses arrived in Britain in 1911, the Schiemann system was well established and was the most common, although the Cédès-Stoll system was tried in West Ham and in Keighley. Smaller trackless trolley systems were built in the US early as well, the trackless trolley was often seen as an interim step, leading to streetcars. Buses and trolleybuses in particular were seen as entry systems that could later be upgraded to rail as appropriate, some trolleybus lines in the United States came into existence when a trolley or tram route did not have sufficient ridership to warrant track maintenance or reconstruction. In a similar manner, a proposed tram scheme in Leeds, worldwide, around 300 cities or metropolitan areas are served by trolleybuses today. See also Trolleybus usage by country, for example, new systems opened in Lecce, Italy, in 2012 and in Malatya, Turkey, in 2015
2.
Tram
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A tram is a rail vehicle which runs on tracks along public urban streets, and also sometimes on a segregated right of way. The lines or networks operated by tramcars are called tramways, Tramways powered by electricity, the most common type historically, were once called electric street railways. However, trams were used in urban areas before the universal adoption of electrification. Tram lines may run between cities and/or towns, and/or partially grade-separated even in the cities. Very occasionally, trams also carry freight, Tram vehicles are usually lighter and shorter than conventional trains and rapid transit trains, but the size of trams is rapidly increasing. Some trams may also run on railway tracks, a tramway may be upgraded to a light rail or a rapid transit line. For all these reasons, the differences between the modes of rail transportation are often indistinct. In the United States, the tram has sometimes been used for rubber-tired trackless trains. Today, most trams use electrical power, usually fed by a pantograph, in some cases by a sliding shoe on a third rail. If necessary, they may have dual power systems — electricity in city streets, trams are now included in the wider term light rail, which also includes segregated systems. The English terms tram and tramway are derived from the Scots word tram, referring respectively to a type of truck used in coal mines and the tracks on which they ran. The word tram probably derived from Middle Flemish trame, a Romanesque word meaning the beam or shaft of a barrow or sledge, the identical word la trame with the meaning crossbeam is also used in the French language. The word Tram-car is attested from 1873, although the terms tram and tramway have been adopted by many languages, they are not used universally in English, North Americans prefer streetcar, trolley, or trolleycar. The term streetcar is first recorded in 1840, and originally referred to horsecars, when electrification came, Americans began to speak of trolleycars or later, trolleys. The troller design frequently fell off the wires, and was replaced by other more reliable devices. The terms trolley pole and trolley wheel both derive from the troller, Modern trams often have an overhead pantograph mechanical linkage to connect to power, abandoning the trolley pole altogether. Conventional diesel tourist buses decorated to look like streetcars are sometimes called trolleys in the US, the term may also apply to an aerial ropeway, e. g. the Roosevelt Island Tramway. Over time, the trolley has fallen into informal use
3.
Electric locomotive
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An electric locomotive is a locomotive powered by electricity from overhead lines, a third rail or on-board energy storage such as a battery or fuel cell. Electricity is used to smoke and take advantage of the high efficiency of electric motors. One advantage of electrification is the lack of pollution from the locomotives, electrification results in higher performance, lower maintenance costs and lower energy costs. Power plants, even if they burn fossil fuels, are far cleaner than mobile sources such as locomotive engines, the power can come from clean or renewable sources, including geothermal power, hydroelectric power, nuclear power, solar power and wind turbines. Electric locomotives are quiet compared to locomotives since there is no engine and exhaust noise. The lack of reciprocating parts means electric locomotives are easier on the track, Electric locomotives are ideal for commuter rail service with frequent stops. They are used on high-speed lines, such as ICE in Germany, Acela in the U. S. Shinkansen in Japan, China Railway High-speed in China, Electric locomotives are used on freight routes with consistently high traffic volumes, or in areas with advanced rail networks. Electric locomotives benefit from the efficiency of electric motors, often above 90%. Additional efficiency can be gained from regenerative braking, which allows energy to be recovered during braking to put power back on the line. Newer electric locomotives use AC motor-inverter drive systems provide for regenerative braking. The chief disadvantage of electrification is the cost for infrastructure, overhead lines or third rail, substations, public policy in the U. S. interferes with electrification, higher property taxes are imposed on privately owned rail facilities if they are electrified. In Europe and elsewhere, railway networks are considered part of the transport infrastructure, just like roads, highways and waterways. Operators of the rolling stock pay fees according to rail use and this makes possible the large investments required for the technically and, in the long-term, also economically advantageous electrification. Because railroad infrastructure is owned in the U. S. railroads are unwilling to make the necessary investments for electrification. The first known electric locomotive was built in 1837 by chemist Robert Davidson of Aberdeen and it was powered by galvanic cells. Davidson later built a locomotive named Galvani, exhibited at the Royal Scottish Society of Arts Exhibition in 1841. The seven-ton vehicle had two direct-drive reluctance motors, with fixed electromagnets acting on iron bars attached to a cylinder on each axle. It hauled a load of six tons at four miles per hour for a distance of one and it was tested on the Edinburgh and Glasgow Railway in September of the following year, but the limited power from batteries prevented its general use
4.
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
5.
Electric power
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Electric power is the rate, per unit time, at which electrical energy is transferred by an electric circuit. The SI unit of power is the watt, one joule per second, Electric power is usually produced by electric generators, but can also be supplied by sources such as electric batteries. It is usually supplied to businesses and homes by the power industry through an electric power grid. Electric power is sold by the kilowatt hour which is the product of power in kilowatts multiplied by running time in hours. Electric utilities measure power using an electricity meter, which keeps a total of the electric energy delivered to a customer. Electrical power provides a low form of energy and can be carried long distances and converted into other forms of energy such as motion. Electric power, like power, is the rate of doing work, measured in watts. The term wattage is used colloquially to mean electric power in watts, the potential energy of the charges due to the voltage between the terminals is converted to kinetic energy in the device. These devices are called passive components or loads, they consume electric power from the circuit, converting it to other forms of such as mechanical work, heat, light. Examples are electrical appliances, such as bulbs, electric motors. In alternating current circuits the direction of the voltage periodically reverses, devices in which this occurs are called active devices or power sources, such as electric generators and batteries. Some devices can be either a source or a load, depending on the voltage, for example, a rechargeable battery acts as a source when it provides power to a circuit, but as a load when it is connected to a battery charger and is being recharged. Since electric power can flow either into or out of a component, Electric power flowing out of a circuit into a component is arbitrarily defined to have a positive sign, while power flowing into a circuit from a component is defined to have a negative sign. Thus passive components have positive power consumption, while power sources have negative power consumption and this is called the passive sign convention. In alternating current circuits, energy storage such as inductance and capacitance may result in periodic reversals of the direction of energy flow. The portion of power flow that, averaged over a cycle of the AC waveform. That portion of power due to stored energy, that returns to the source in each cycle, is known as reactive power. Real power is represented as a vector and reactive power is represented as a vertical vector
6.
Overhead line
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An overhead line or overhead wire is used to transmit electrical energy to trams, trolleybuses, or trains. Overhead line is designed on the principle of one or more overhead wires situated over rail tracks, the feeder stations are usually fed from a high-voltage electrical grid. Electric trains that collect their current from overhead lines use a device such as a pantograph and it presses against the underside of the lowest overhead wire, the contact wire. Current collectors are electrically conductive and allow current to flow through to the train or tram, non-electric locomotives may pass along these tracks without affecting the overhead line, although there may be difficulties with overhead clearance. Alternative electrical power transmission schemes for trains include third rail, ground-level power supply, batteries and this article does not cover regenerative braking, where the traction motors act as generators to retard movement and return power to the overhead. To achieve good high-speed current collection, it is necessary to keep the wire geometry within defined limits. This is usually achieved by supporting the wire from a second wire known as the messenger wire or catenary. This wire approximates the path of a wire strung between two points, a catenary curve, thus the use of catenary to describe this wire or sometimes the whole system. This wire is attached to the wire at regular intervals by vertical wires known as droppers or drop wires. It is supported regularly at structures, by a pulley, link, the whole system is then subjected to a mechanical tension. As the contact wire makes contact with the pantograph, the insert on top of the pantograph is worn down. The straight wire between supports will cause the wire to cross over the whole surface of the pantograph as the train travels around the curve, causing uniform wear. On straight track, the wire is zigzagged slightly to the left. The movement of the wire across the head of the pantograph is called the sweep. The zigzagging of the line is not required for trolley poles. Depot areas tend to have only a wire and are known as simple equipment or trolley wire. When overhead line systems were first conceived, good current collection was only at low speeds. Compound equipment - uses a second wire, known as the auxiliary
7.
Third rail
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A third rail is a method of providing electric power to a railway locomotive or train, through a semi-continuous rigid conductor placed alongside or between the rails of a railway track. It is used typically in a transit or rapid transit system. Third rail systems are supplied from direct current electricity. The third-rail system of electrification is unrelated to the third used in dual gauge railways. Third-rail systems are a means of providing electric power to trains. On most systems, the rail is placed on the sleeper ends outside the running rails. The conductor rail is supported on ceramic insulators or insulated brackets, the trains have metal contact blocks called shoes which make contact with the conductor rail. The traction current is returned to the station through the running rails. The conductor rail is made of high conductivity steel. The conductor rails have to be interrupted at level crossings, crossovers, tapered rails are provided at the ends of each section, to allow a smooth engagement of the trains contact shoes. Because third rail systems present electric shock hazards close to the ground, a very high current must therefore be used to transfer adequate power, resulting in high resistive losses, and requiring relatively closely spaced feed points. The electrified rail threatens electrocution of anyone wandering or falling onto the tracks. This can be avoided by using platform screen doors, or the risk can be reduced by placing the rail on the side of the track away from the platform. There is also a risk of pedestrians walking onto the tracks at level crossings, the Paris Metro has graphic warning signs pointing out the danger of electrocution from urinating on third rails, precautions which Chicago did not have. The end ramps of conductor rails present a practical limitation on speed due to the impact of the shoe. The world speed record for a rail train is 174 km/h attained on 11 April 1988 by a British Class 442 EMU. In the event of a collision with an object, the beveled end ramps of bottom running systems can facilitate the hazard of having third rail penetrate the interior of a passenger car. This is believed to have contributed to the death of five passengers in the Valhalla train crash of 2015, third rail systems using top contact are prone to accumulations of snow, or ice formed from refrozen snow, and this can interrupt operations
8.
Electrical resistivity and conductivity
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Electrical resistivity is an intrinsic property that quantifies how strongly a given material opposes the flow of electric current. A low resistivity indicates a material that allows the flow of electric current. Resistivity is commonly represented by the Greek letter ρ, the SI unit of electrical resistivity is the ohm-metre. Electrical conductivity or specific conductance is the reciprocal of electrical resistivity and it is commonly represented by the Greek letter σ, but κ or γ are also occasionally used. Its SI unit is siemens per metre and CGSE unit is reciprocal second, many resistors and conductors have a uniform cross section with a uniform flow of electric current, and are made of one material. All copper wires, irrespective of their shape and size, have approximately the same resistivity, every material has its own characteristic resistivity – for example, resistivity of rubber is far larger than coppers. If the pipes are the size and shape, the pipe full of sand has higher resistance to flow. Resistance, however, is not solely determined by the presence or absence of sand and it also depends on the length and width of the pipe, short or wide pipes have lower resistance than narrow or long pipes. The above equation can be transposed to get Pouillets law, R = ρ ℓ A, the resistance of a given material increases with length, but decreases with increasing cross-sectional area. From the above equations, resistivity has the SI unit ohm metre, the formula R = ρ ℓ / A can be used to intuitively understand the meaning of a resistivity value. For example, if A = 7000100000000000000♠1 m2 ℓ = 7000100000000000000♠1 m, Conductivity, σ, is defined as the inverse of resistivity, σ =1 ρ. Conductivity has SI units of siemens per metre, the above definition was specific to resistors or conductors with a uniform cross-section, where current flows uniformly through them. A more basic and general definition starts from the fact that a field inside a material makes electric current flow. Conductivity is the inverse, σ =1 ρ = J E, for example, rubber is a material with large ρ and small σ—because even a very large electric field in rubber makes almost no current flow through it. On the other hand, copper is a material with small ρ, according to elementary quantum mechanics, electrons in an atom do not take on arbitrary energy values. Rather, electrons only occupy discrete energy levels in an atom or crystal. When a large number of such allowed energy levels are spaced close together —i. e. have similar energies— we can talk about these energy levels together as an energy band. There can be many such bands in a material, depending on the atomic number
9.
Insulator (electricity)
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An electrical insulator is a material whose internal electric charges do not flow freely, very little electric current will flow through it under the influence of an electric field. This contrasts with other materials, semiconductors and conductors, which conduct electric current more easily, the property that distinguishes an insulator is its resistivity, insulators have higher resistivity than semiconductors or conductors. A perfect insulator does not exist, because even insulators contain small numbers of mobile charges which can carry current, in addition, all insulators become electrically conductive when a sufficiently large voltage is applied that the electric field tears electrons away from the atoms. This is known as the voltage of an insulator. Some materials such as glass, paper and Teflon, which have high resistivity, are good electrical insulators. Examples include rubber-like polymers and most plastics which can be thermoset or thermoplastic in nature, insulators are used in electrical equipment to support and separate electrical conductors without allowing current through themselves. An insulating material used in bulk to wrap electrical cables or other equipment is called insulation, the term insulator is also used more specifically to refer to insulating supports used to attach electric power distribution or transmission lines to utility poles and transmission towers. They support the weight of the suspended wires without allowing the current to flow through the tower to ground, electrical insulation is the absence of electrical conduction. Electronic band theory says that a charge flows if states are available into which electrons can be excited and this allows electrons to gain energy and thereby move through a conductor such as a metal. If no such states are available, the material is an insulator, most insulators have a large band gap. This occurs because the valence band containing the highest energy electrons is full, there is always some voltage that gives electrons enough energy to be excited into this band. Once this voltage is exceeded the material ceases being an insulator, however, it is usually accompanied by physical or chemical changes that permanently degrade the materials insulating properties. Materials that lack electron conduction are insulators if they lack other mobile charges as well, for example, if a liquid or gas contains ions, then the ions can be made to flow as an electric current, and the material is a conductor. Electrolytes and plasmas contain ions and act as conductors whether or not electron flow is involved, when subjected to a high enough voltage, insulators suffer from the phenomenon of electrical breakdown. These freed electrons and ions are in turn accelerated and strike other atoms, creating more charge carriers, rapidly the insulator becomes filled with mobile charge carriers, and its resistance drops to a low level. In a solid, the voltage is proportional to the band gap energy. The air in a region around a conductor can break down and ionise without a catastrophic increase in current. Even a vacuum can suffer a sort of breakdown, but in case the breakdown or vacuum arc involves charges ejected from the surface of metal electrodes rather than produced by the vacuum itself
10.
Switch
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In electrical engineering, a switch is an electrical component that can make or break an electrical circuit, interrupting the current or diverting it from one conductor to another. The mechanism of a switch removes or restores the conducting path in a circuit when it is operated, the most familiar form of switch is a manually operated electromechanical device with one or more sets of electrical contacts, which are connected to external circuits. The mechanism actuating the transition between two states can be either a toggle or momentary type. A switch may be manipulated by a human as a control signal to a system, such as a computer keyboard button, or to control power flow in a circuit. Switches may be operated by process variables such as pressure, temperature, flow, current, voltage, for example, a thermostat is a temperature-operated switch used to control a heating process. A switch that is operated by electrical circuit is called a relay. Large switches may be operated by a motor drive mechanism. An ideal switch would have no voltage drop when closed, and it would have zero rise time and fall time during state changes, and would change state without bouncing between on and off positions. Practical switches fall short of ideal, they have resistance, limits on the current and voltage they can handle, finite switching time. The ideal switch is used in circuit analysis as it greatly simplifies the system of equations to be solved. Theoretical treatment of the effects of non-ideal properties is required in the design of networks of switches. In the simplest case, a switch has two pieces, often metal, called contacts, connected to an external circuit, that touch to complete the circuit. The contact material is chosen for its resistance to corrosion, because most metals form insulating oxides that would prevent the switch from working, contact materials are also chosen on the basis of electrical conductivity, hardness, mechanical strength, low cost and low toxicity. Sometimes the contacts are plated with noble metals and they may be designed to wipe against each other to clean off any contamination. Nonmetallic conductors, such as plastic, are sometimes used. To prevent the formation of insulating oxides, a minimum wetting current may be specified for a given switch design, in electronics, switches are classified according to the arrangement of their contacts. A pair of contacts is said to be closed when current can flow from one to the other, when the contacts are separated by an insulating air gap, they are said to be open, and no current can flow between them at normal voltages. The terms make for closure of contacts and break for opening of contacts are also widely used, the terms pole and throw are also used to describe switch contact variations
11.
Transformer
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A transformer is an electrical device that transfers electrical energy between two or more circuits through electromagnetic induction. A varying current in one coil of the transformer produces a magnetic field. Power can be transferred between the two coils through the field, without a metallic connection between the two circuits. Faradays law of induction discovered in 1831 described this effect, Transformers are used to increase or decrease the alternating voltages in electric power applications. A wide range of designs is encountered in electronic and electric power applications. Transformers range in size from RF transformers less than a centimeter in volume to units interconnecting the power grid weighing hundreds of tons. For simplification or approximation purposes, it is common to analyze the transformer as an ideal transformer model as presented in the two images. An ideal transformer is a theoretical, linear transformer that is lossless and perfectly coupled, perfect coupling implies infinitely high core magnetic permeability and winding inductances and zero net magnetomotive force. A varying current in the primary winding creates a varying magnetic flux in the transformer core. This varying magnetic field at the secondary winding induces a varying EMF or voltage in the secondary winding due to electromagnetic induction. The primary and secondary windings are wrapped around a core of high magnetic permeability so that all of the magnetic flux passes through both the primary and secondary windings. With a voltage source connected to the winding and load impedance connected to the secondary winding. The primary EMF is sometimes termed counter EMF and this is in accordance with Lenzs law, which states that induction of EMF always opposes development of any such change in magnetic field. The transformer winding voltage ratio is shown to be directly proportional to the winding turns ratio according to eq. common usage having evolved over time from turn ratio to turns ratio. However, some use the inverse definition. The ideal transformer model assumes that all flux generated by the primary winding links all the turns of winding, including itself. In practice, some flux traverses paths that take it outside the windings, Such flux is termed leakage flux, and results in leakage inductance in series with the mutually coupled transformer windings. Leakage flux results in energy being alternately stored in and discharged from the fields with each cycle of the power supply
12.
Electric motor
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An electric motor is an electrical machine that converts electrical energy into mechanical energy. The reverse of this is the conversion of energy into electrical energy and is done by an electric generator. In normal motoring mode, most electric motors operate through the interaction between an electric motors magnetic field and winding currents to generate force within the motor, small motors may be found in electric watches. General-purpose motors with highly standardized dimensions and characteristics provide convenient mechanical power for industrial use, the largest of electric motors are used for ship propulsion, pipeline compression and pumped-storage applications with ratings reaching 100 megawatts. Electric motors may be classified by electric power source type, internal construction, application, type of motion output, perhaps the first electric motors were simple electrostatic devices created by the Scottish monk Andrew Gordon in the 1740s. The theoretical principle behind production of force by the interactions of an electric current. The conversion of energy into mechanical energy by electromagnetic means was demonstrated by the British scientist Michael Faraday in 1821. A free-hanging wire was dipped into a pool of mercury, on which a permanent magnet was placed, when a current was passed through the wire, the wire rotated around the magnet, showing that the current gave rise to a close circular magnetic field around the wire. This motor is often demonstrated in experiments, brine substituting for toxic mercury. Though Barlows wheel was a refinement to this Faraday demonstration. In 1827, Hungarian physicist Ányos Jedlik started experimenting with electromagnetic coils, after Jedlik solved the technical problems of the continuous rotation with the invention of the commutator, he called his early devices electromagnetic self-rotors. Although they were used only for instructional purposes, in 1828 Jedlik demonstrated the first device to contain the three components of practical DC motors, the stator, rotor and commutator. The device employed no permanent magnets, as the fields of both the stationary and revolving components were produced solely by the currents flowing through their windings. His motor set a record which was improved only four years later in September 1838 by Jacobi himself. His second motor was powerful enough to drive a boat with 14 people across a wide river and it was not until 1839/40 that other developers worldwide managed to build motors of similar and later also of higher performance. The first commutator DC electric motor capable of turning machinery was invented by the British scientist William Sturgeon in 1832, following Sturgeons work, a commutator-type direct-current electric motor made with the intention of commercial use was built by the American inventor Thomas Davenport, which he patented in 1837. The motors ran at up to 600 revolutions per minute, and powered machine tools, due to the high cost of primary battery power, the motors were commercially unsuccessful and Davenport went bankrupt. Several inventors followed Sturgeon in the development of DC motors but all encountered the same battery power cost issues, no electricity distribution had been developed at the time
13.
Rail profile
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The rail profile is the cross sectional shape of a railway rail, perpendicular to its length. Early rails were made of wood, cast iron or wrought iron, all modern rails are hot rolled steel with a cross section approximate to an I-beam, but asymmetric about a horizontal axis. The head is profiled to resist wear and to give a ride. Unlike some other uses of iron and steel, railway rails are subject to high stresses and are made of very high quality steel. It took many decades to improve the quality of the materials, minor flaws in the steel that may pose no problems in other applications can lead to broken rails and dangerous derailments when used on railway tracks. By and large, the heavier the rails and the rest of the trackwork, the rails represent a substantial fraction of the cost of a railway line. Only a small number of sizes are made by steelworks at one time. Worn, heavy rail from a mainline is often reclaimed and downgraded for re-use on a branchline, the weight of a rail per length is an important factor in determining rails strength and hence axleloads and speeds. Weights are measured in pounds per yard or kilograms per metre, rails in Canada, the United Kingdom and United States are described using imperial units. In Australia, metric units are used as in mainland Europe, commonly, in rail terminology Pound is a contraction of the expression pounds per yard and hence a 132–pound rail means a rail of 132 pounds per yard. Rails are made in a number of different sizes. Some common European rail sizes include, In the countries of former USSR65 kg/m rails and 75 kg/m rails are common, the American Society of Civil Engineers specified rail profiles in 1893 for 5-pound-per-yard increments from 40 to 100 lb/yd. Height of rail equaled width of foot for each ASCE tee-rail weight, ASCE90 lb/yd profile was adequate, but heavier weights were less satisfactory. In 1909, the American Railway Association specified standard profiles for 10 lb/yd increments from 60 to 100 lb/yd, the trend was to increase rail height/foot-width ratio and strengthen the web. Disadvantages of the foot were overcome through use of tie-plates. AREA recommendations reduced the weight of rail head down to 36%. Attention was also focused on improved fillet radii to reduce stress concentration at the web junction with the head, AREA recommended the ARA90 lb/yd profile. Old ASCE rails of lighter weight remained in use, and satisfied the demand for light rail for a few decades
14.
Track (rail transport)
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The track on a railway or railroad, also known as the permanent way, is the structure consisting of the rails, fasteners, railroad ties and ballast, plus the underlying subgrade. It enables trains to move by providing a surface for their wheels to roll upon. For clarity it is referred to as railway track or railroad track. Tracks where electric trains or electric trams run are equipped with a system such as an overhead electrical power line or an additional electrified rail. The term permanent way also refers to the track in addition to structures such as fences etc. Most railroads with heavy traffic use continuously welded rails supported by sleepers attached via baseplates that spread the load, a plastic or rubber pad is usually placed between the rail and the tieplate where concrete sleepers are used. The rail is held down to the sleeper with resilient fastenings. For much of the 20th century, rail track used softwood timber sleepers and jointed rails, jointed rails were used at first because contemporary technology did not offer any alternative. The joints also needed to be lubricated, and wear at the mating surfaces needed to be rectified by shimming. For this reason jointed track is not financially appropriate for heavily operated railroads, timber sleepers are of many available timbers, and are often treated with creosote, copper-chrome-arsenic, or other wood preservative. Pre-stressed concrete sleepers are used where timber is scarce and where tonnage or speeds are high. Steel is used in some applications, the track ballast is customarily crushed stone, and the purpose of this is to support the sleepers and allow some adjustment of their position, while allowing free drainage. A disadvantage of traditional track structures is the demand for maintenance, particularly surfacing and lining to restore the desired track geometry. Weakness of the subgrade and drainage deficiencies also lead to maintenance costs. This can be overcome by using ballastless track, in its simplest form this consists of a continuous slab of concrete with the rails supported directly on its upper surface. There are a number of systems, and variations include a continuous reinforced concrete slab. Many permutations of design have been put forward, however, ballastless track has a high initial cost, and in the case of existing railroads the upgrade to such requires closure of the route for a long period. Its whole-life cost can be lower because of the reduction in maintenance, some rubber-tyred metros use ballastless tracks
15.
Ground (electricity)
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Electrical circuits may be connected to ground for several reasons. In mains powered equipment, exposed parts are connected to ground to prevent user contact with dangerous voltage when electrical insulation fails. In electrical power systems, a protective ground conductor is an essential part of the safety Earthing system. Connection to ground also limits the build-up of static electricity when handling flammable products or electrostatic-sensitive devices, in some telegraph and power transmission circuits, the earth itself can be used as one conductor of the circuit, saving the cost of installing a separate return conductor. For measurement purposes, the Earth serves as a constant potential reference against which other potentials can be measured, an electrical ground system should have an appropriate current-carrying capability to serve as an adequate zero-voltage reference level. In electronic circuit theory, a ground is usually idealized as a source or sink for charge. Where a real ground connection has a significant resistance, the approximation of zero potential is no longer valid, stray voltages or earth potential rise effects will occur, which may create noise in signals or if large enough will produce an electric shock hazard. This is usually a large conductor attached to one side of the power supply which serves as the return path for current from many different components in the circuit. Long-distance electromagnetic telegraph systems from 1820 onwards used two or more wires to carry the signal and return currents. During dry weather, the ground connection often developed a high resistance, an electrical connection to earth can be used as a reference potential for radio frequency signals for certain kinds of antennas. The part directly in contact with the earth - the earth electrode - can be as simple as a rod or stake driven into the earth. Because high frequency signals can flow to earth due to capacitative effects, because of this, a complex system of buried rods and wires can be effective. An ideal signal ground maintains a fixed potential regardless of how much current flows into ground or out of ground. Some types of transmitting antenna systems in the VLF, LF, MF, sometimes a counterpoise is used as a ground plane, supported above the ground. Electrical power distribution systems are connected to ground to limit the voltage that can appear on distribution circuits. A distribution system insulated from ground may attain a high potential due to transient voltages caused by arcing, static electricity, a ground connection of the system dissipates such potentials and limits the rise in voltage of the grounded system. In a mains electricity wiring installation, the ground conductor typically refers to three different conductors or conductor systems as listed below. Equipment earthing conductors provide a connection between non-current-carrying metallic parts of equipment and the earth
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Pantograph (transport)
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A pantograph is an apparatus mounted on the roof of an electric train, tram or electric bus to collect power through contact with an overhead catenary wire. It is a type of current collector. Typically, a wire is used, with the return current running through the track. The term stems from the resemblance of some styles to the mechanical pantographs used for copying handwriting, the pantograph was invented in 1879 by Walter Reichel, chief engineer at Siemens & Halske in Germany. A flat slide-pantograph was invented in 1895 at the Baltimore and Ohio Railroad The familiar diamond-shaped roller pantograph was invented by John Q. Brown of the Key System shops for their commuter trains ran between San Francisco and the East Bay section of the San Francisco Bay Area in California. They appear in photographs of the first day of service,26 October 1903, for many decades thereafter, the same diamond shape was used by electric-rail systems around the world and remains in use by some today. The most common type of today is the so-called half-pantograph. Louis Faiveley invented this type of pantograph in 1955, the half-pantograph can be seen in use on everything from very fast trains to low-speed urban tram systems. The electric transmission system for electric rail systems consists of an upper. The pantograph is spring-loaded and pushes a contact shoe up against the underside of the wire to draw the current needed to run the train. The steel rails of the act as the electrical return. As the train moves, the shoe slides along the wire and can set up standing waves in the wires which break the contact. This means that on some systems adjacent pantographs are not permitted, pantographs are the successor technology to trolley poles, which were widely used on early streetcar systems. However, many of these networks, including Torontos, are undergoing upgrades to accommodate pantograph operation, as a precaution against loss of pressure in the second case, the arm is held in the down position by a catch. For high-voltage systems, the air supply is used to blow out the electric arc when roof-mounted circuit breakers are used. Pantographs may have either a single or a double arm, double-arm pantographs are usually heavier, requiring more power to raise and lower, but may also be more fault-tolerant. On railways of the former USSR, the most widely used pantographs are those with a double arm, some streetcars use double-arm pantographs, among them the Russian KTM-5, KTM-8, LVS-86 and many other Russian-made trams, as well as some Euro-PCC trams in Belgium
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Bow collector
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A bow collector is one of the three main devices used on tramcars to transfer electric current from the wires above to the tram below. While once very common in continental Europe, it was replaced by the pantograph or the trolley pole, to avoid contravening this patent, the Siemens company was forced to design its own, unique form of current collection, namely the bow collector. The bow collector was first used by the Siemens electric company in its early electric tramcars in either the late 1880s or early 1890s. The Hobart electric tramway system - the first of its kind in the Southern Hemisphere, many other continental European and some British tramway systems, including Leeds and Glasgow, also used this method. The bow collector is one of the simplest and most reliable methods of current collection used on tramways, the very earliest versions were simply very heavy-gauge wire or steel bars bent into a rectangular shape and mounted long-side-down on the tramcar roof. The height of the collector was such that its top edge would scrape along the wire above, the top section is made of a 1-inch broad steel rod, machined to have a bow-shaped cross section, hence the name. This bow shaped rod is referred to as the collector plate, unlike many trolley poles, the bow collector does not normally have a revolving base, but is rather fixed centrally to the tramcar roof. In the late 1900s the simple framing methods mentioned above were gradually replaced by more complex and sophisticated methods, the changes of design are most noticeable on systems where both double- and single-deck cars were used on the same system. The steel rails on the act as the electrical return. Properly the bow collector should be mounted in such a way so that the top edge of the plate would rise several inches above the wire when the collector frame is standing straight up. Thus the collector usually leans opposite to the direction of travel, when the comes to travel in the opposite direction. To allow this to happen, the wire must be raised by several inches at places where the bows are swung over, such as terminals. This operation is achieved by ropes and pulleys. The collector is folded down to a position when the car is not in use. Some early cars had no means to swing the bows over and it was thought that this would happen automatically when the tramcar started travelling the other way, but collectors such as these were a failure. Most Soviet trams had no means to swing the bows over and these trams were not designed to travel two ways. Another example is KTV-55-2 tramcar which had two bow collectors for the two directions of travelling, the bow collector has fewer moving parts than the trolley pole, but is heavier and sometimes more complicated to construct. The construction of overhead wires for bow collectors is simpler than trolley pole wiring, as bow collectors do not have revolving mountings, the collector cannot jump off the wire or follow the wrong one at intersections, as trolley poles sometimes do
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Trolley pole
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A trolley pole is a tapered cylindrical pole of wood or metal, used to transfer electricity from a live overhead wire to the control and the electric traction motors of a tram or trolley bus. It is a type of current collector, the term trolley predates the invention of the trolley pole. From the side, the lines made the car seem to be trolling. Later, when a pivoted pole replaced the troller, it came to be known as a trolley pole, an early development of an experimental tramway in Toronto, Ontario was built in 1883, having been developed by John Joseph Wright, brother of swindler Whitaker Wright. While Wright may have assisted in the installation of railways at the Canadian National Exhibition. Likewise, Wright never filed or was issued a patent, credit for development of the first working trolley pole is given to Charles Joseph Van Depoele, a Belgian engineer who moved to the United States in 1869. Van Depoele made the first public demonstration of the device on a temporary streetcar line installed at the Toronto Industrial Exhibition in autumn 1885. However, within a few months, Van Depoele switched to the system for the Montgomery operation. The grooved trolley wheel was used on large city systems through the 1940s and 1950s. The newer sliding carbon trolley shoe was generally used with a newer grooved overhead trolley wire of a roughly figure 8 cross section, the sliding trolley shoe provided better electrical contact, and it dramatically reduced overhead wire wear. Many systems began converting to the trolley shoe in the 1920s, Milwaukee. Curiously, Philadelphia did not convert its trolley wheels on its remaining streetcars until 1978, although a streetcar with a trolley wheel may evoke an antique look, the trolley shoe is modern and more practical as well as economical. A trolley pole is not attached to the overhead wire, the pole sits atop a sprung base on the roof of the vehicle, with springs providing the pressure to keep the trolley wheel or shoe in contact with the wire. If the pole is made of wood, a cable brings the current down to the vehicle. A metal pole may use such a cable, or may itself be electrically live, requiring the base to be insulated from the vehicle body. At terminus points, the conductor must turn the pole around to face the correct direction, pulling it off the wire either with a rope or a pole. In some cases, two poles are provided, one for each direction, in this case it is a matter of raising one. Since the operator could raise the pole at one end whilst the conductor lowered the other, care must be taken to raise the downed pole first, to eliminate the damage caused by arcing between the pole and wire
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Three-phase AC railway electrification
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Three-phase AC railway electrification was used in Italy, Switzerland and the United States in the early twentieth century. The first standard line was in Switzerland, from Burgdorf to Thun. The system provides regenerative braking with the power fed back to the system, the locomotives use three-phase induction motors. Lacking brushes and commutators, they require less maintenance, the early Italian and Swiss systems used a low frequency, and a relatively low voltage compared with later AC systems. Train speed was restricted to one to four speeds, with two or four speeds obtained by pole-changing or cascade operation or both, the following is a list of the railways that have used this method of electrification in the past, The Cascade Tunnel of the Great Northern Railway. The Giovi Railway between Genoa and Pontedecimo in Italy, the Santa Fe - Gergal line in Spain. The Simplon Tunnel between Switzerland and Italy, the Valtellina Line of Italian State Railways. The system is used today for four rack railways, where the overhead wiring is less complicated. New motive power avoids speed restrictions as it is built with solid-state converters, the four systems are as follows, The Corcovado Rack Railway in Rio de Janeiro Brazil. The Petit train de la Rhune in France, still using the original locomotives of 1912 They are nowadays industrial rather than low frequency, usually the locomotives had one, two or four motors on the body chassis, and did not require gearing. The induction motors are designed to run at a particular speed. Pole changing and cascade working was used to two or four different speeds, and resistances were required for starting. In Italy freight locomotives used plain cascade with two speeds,25 and 50 km/h, while express locomotives used cascade combined with pole-changing giving four speeds,37,50,75 and 100 km/h. With the use of 3,000 or 3,600 volts at 16⅔ Hz and this motor characteristic led to a mishap in the Cascade Tunnel to a GN east-bound freight train with four electric locos, two on the head and two pushing. The two pushers suddenly lost power and the train slowed to a stop. But the lead engineer was unaware that his train had stopped. Not seeing daylight, he shut down the locomotive. Generally two separate wires are used, with the rail for the third phase, though occasionally three overhead wires are used
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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
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Tunnel
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A tunnel is an underground passageway, dug through the surrounding soil/earth/rock and enclosed except for entrance and exit, commonly at each end. A pipeline is not a tunnel, though some recent tunnels have used immersed tube construction techniques rather than traditional tunnel boring methods, a tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. The central portions of a transit network are usually in tunnel. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers, utility tunnels are used for routing steam, chilled water, electrical power or telecommunication cables, as well as connecting buildings for convenient passage of people and equipment. Secret tunnels are built for military purposes, or by civilians for smuggling of weapons, contraband, special tunnels, such as wildlife crossings, are built to allow wildlife to cross human-made barriers safely. A tunnel is relatively long and narrow, the length is much greater than twice the diameter, although similar shorter excavations can be constructed. The definition of what constitutes a tunnel can vary widely from source to source, for example, the definition of a road tunnel in the United Kingdom is defined as a subsurface highway structure enclosed for a length of 150 metres or more. In the United States, the NFPA definition of a tunnel is An underground structure with a length greater than 23 m. The place where a road, railway, canal or watercourse passes under a footpath, cycleway, or another road or railway is most commonly called a bridge or, if passing under a canal, an aqueduct. Where it is important to stress that it is passing underneath, it may be called an underpass, a longer underpass containing a road, canal or railway is normally called a tunnel, whether or not it passes under another item of infrastructure. An underpass of any length under a river is usually called a tunnel. In the US, the term means an underground rapid transit system. Rail station platforms may be connected by tunnels or footbridges. Much of the technology of tunneling evolved from mining and military engineering. The etymology of the mining, military engineering, and civil engineering reveals these deep historic connections. A major tunnel project must start with an investigation of ground conditions by collecting samples from boreholes. An informed choice can then be made of machinery and methods for excavation and ground support, in planning the route, the horizontal and vertical alignments can be selected to make use of the best ground and water conditions. It is common practice to locate a tunnel deeper than otherwise would be required and this may be a particular concern in large-diameter tunnels
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Bogie
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A bogie is a chassis or framework carrying wheels, attached to a vehicle, thus serving as a modular subassembly of wheels and axles. Bogies take various forms in various modes of transport, while bogie is the preferred spelling and first-listed variant in various dictionaries, bogey and bogy are also used. A bogie in the UK, or a truck, wheel truck. In Indian English, bogie may also refer to a railway carriage. In South Africa, the bogie is often alternatively used to refer to a freight or goods wagon. The first standard gauge British railway to build coaches with bogies, an alternate configuration often is used in articulated vehicles, which places the bogies under the connection between the carriages or wagons. Most bogies have two axles, but some cars designed for heavy loads have more axles per bogie, heavy-duty cars may have more than two bogies using span bolsters to equalize the load and connect the bogies to the cars. Suspension to absorb shocks between the frame and the rail vehicle body, Common types are coil springs, or rubber airbags. At least one wheelset, composed of an axle with bearings and a wheel at each end The bolster, the railway car is supported at the pivot point on the bolster. Axle box suspensions absorb shocks between the bearings and the bogie frame. The axle box suspension usually consists of a spring between the frame and axle bearings to permit up-and-down movement, and sliders to prevent lateral movement. A more modern design uses solid rubber springs, brake equipment, Two main types are used, brake shoes that are pressed against the tread of the wheel, and disc brakes and pads. More modern, bolsterless bogie designs omit these features, instead taking advantage of the movement of the suspension to permit rotational movement. The Commonwealth bogie, manufactured by the English Steel Corporation under licence from the Commonwealth Steel Company in Illinois, fitted with SKF or Timken bearings, it was introduced in the late 1950s for all BR Mark 1 vehicles. It was a heavy, cast-steel design weighing about 6.5 long tons, with sealed roller bearings on the axle ends, the leaf springs were replaced by coil springs running vertically rather than horizontally. The advanced design gave a better quality than the BR1. The side frame of the bogie was usually of bar construction, with simple horn guides attached, the axle boxes had a cast-steel equaliser beam or bar resting on them. The bar had two steel coil springs placed on it and the bogie frame rested on the springs, the effect was to allow the bar to act as a compensating lever between the two axles and to use both springs to soften shocks from either axle
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Rubber-tyred metro
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A rubber-tyred metro is a form of rapid transit system that uses a mix of road and rail technology. Most rubber-tyred trains are purpose-built and designed for the system on which they operate, guided buses are sometimes referred to as trams on tyres, and compared to rubber-tyred metros. The first idea for rubber-tyred railway vehicles was the work of Scotsman Robert William Thomson, in his patent of 1846 he describes his Aerial Wheels as being equally suitable for, the ground or rail or track on which they run. During the World War II German occupation of Paris, the Metro system was used to capacity, at the end of the war, the system was so worn out that thought was given as to how to renovate it. Rubber-tyred metro technology was first applied to the Paris Métro, developed by Michelin, who provided the tyres and guidance system, in collaboration with Renault, who provided the vehicles. Starting in 1951, a vehicle, the MP51. Line 11 Châtelet - Mairie des Lilas was the first line to be converted, in 1956, finally, Line 6 Charles de Gaulle - Étoile - Nation was converted in 1974 to cut down train noise on its many elevated sections. The first completely rubber-tyred metro system was built in Montreal, Canada, santiago Metro and Mexico City Metro are based on Paris Métro rubber-tyred trains. Paris Metro Line 14 was automated from its beginning, and Line 1 was converted to automatic in 2007-2011, the first automated rubber-tyred system opened in Kobe, Japan, in February 1981. It is the Portliner linking Sanomiya railway station with Port Island, the vehicle is in the form of electric multiple unit, with power supplied by both, of the guide bars, which thus also serves as the third rail. The return current passes through a return shoe to the top of one, the type of guideway used on a system varies between networks. Two parallel roll ways, each the width of a tyre, are used, either of concrete, concrete slab, H-Shape hot rolled steel, or flat steel. As on a railway, the driver does not have to steer, the Sapporo system is an exception as it uses a central guide rail only. The VAL system used in Lille and Toulouse has conventional track between the guide bars, in Paris these rails were also used to enable mixed traffic with rubber-tyred and steel-wheeled trains using the same track, particularly during conversion from normal railway track. Other systems have other sorts of flat tyre compensation and switching methods, rubber-tyres have higher rolling resistance when compared to traditional steel wheels, which leads to some advantages and disadvantages. Compared to steel wheel on rail, the advantages of rubber-tyred metro systems are. Shorter braking distances, allowing trains to be signalled closer together, quieter rides in open air due to use rubber-tyre. Greatly reduced rail wear with resulting reduced costs of those parts
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Ground-level power supply
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Ground-level power supply, also known as surface current collection and Alimentation par le Sol, is a modern method of third-rail electrical pick-up for street trams. It was invented for the Bordeaux tramway, which was constructed from 2000, until 2011, this was the only place it was used, with proposals to install it elsewhere. Reims has adopted this technology for its new Reims Tramway, which was opened in 2011, as have Angers, ground-level power supply is used, primarily for aesthetic reasons, as an alternative to overhead lines. Conduit current collection was used in historic tram systems in Washington, Manhattan, Paris, Berlin, Marseilles, Vienna, Budapest, in Prague on the Charles Bridge a system invented by František Křižík was used, similar to todays APS. Unlike the track-side third rail used by most metro trains and some railways, APS does not pose a danger to people or animals and so can be used in pedestrian areas. APS uses a third rail placed between the rails, divided electrically into ten-metre rail segments with three-metre neutral sections between. Each tram has two power collection shoes, next to which are antennas that send signals to energise the power rail segments as the tram passes over them. At any one time, two consecutive segments under the tram will be live, modern ground-level current collection was pioneered by the Bordeaux tramway in France. Facing complaints both from the public and the French Ministry of Culture, planners developed APS as a way of replicating the conduit system. APS was developed by Innorail, a subsidiary of Spie Enertrans but was sold to Alstom when Spie was acquired by Amec, there are 12 km of APS tramway in the three-line network of 43.3 km as of 2008. Bordeaux Citadis trams use pantographs and electric lines in outlying areas. Before use in Bordeaux, APS was tested and proved viable on a section of reserved-track in the French city of Marseille. Problems have included water-logging, when the water does not drain quickly enough after heavy rain, in July 2006, it was announced that two new French tram systems would be using APS over part of their networks. These are located in Angers and Reims, with both opening in 2011. The Dubai Tram, which opened in 2014, is equipped with APS over its entire passenger length. The predecessors of APS were developed around 1900, and used by several companies in Paris. Associated with these systems were the inventors Dolter and Diatto, each contact contained a fuse, which would be blown by an earthed safety shoe on the rear of the tram should the contact not have switched out. This proved to be unsatisfactory because the strong currents melted down the switch contacts, another system of ground-level power supply was used by Budapest trams from 1887
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Conduit current collection
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Conduit current collection is a system of electric current collection used by electric tramways, where the power supply was carried in a conduit under the roadway. The power rails are contained in a conduit midway between and below the two rails on which the cars operate, in much the same fashion as the cable for cable cars. The conduit contains two T section steel rails of opposite polarity facing each other, about 12 inches apart. Power reached the car by means of an attachment, called a plough, the plough had two metal shoes attached to springs that pushed sideways against the power rails. The current was carried by a cable from the plough through the platform to the cars controller. The running rails are not part of the electrical circuit, in the United States, the cars were sometimes popularly but incorrectly called trolleys but did not typically draw power through a trolley pole from an overhead wire as trolley cars do. Conduit current collection was one of the first ways of supplying power to trams but it proved to be more expensive, complicated. In Denver, Colorado, the second electric street railway in 1885 pioneered conduit current collection. Difficulties with the conduit and the led to the replacement of conduit cars. Trolley lines from Brooklyn and Queens also entered Manhattan under wire, the primary reason for the initial adoption of conduit systems was for aesthetic reasons as an alternative to overhead wiring that was often objected to as being unsightly. The expense of creating conduit lines in New York was reduced where it was possible to convert the cable vaults from discontinued cable car lines. The huge cost of building new conduits gave New York the distinction of having one of the last horsecar lines in the U. S. not closing until 1917, in some old photographs, two slots may be seen between the rails. In New York City, sometimes one slot was used for a cable line, occasionally, two competitive lines shared a common track and had independent slots for the ploughs of the respective cars. In New York City, the Queensboro Bridge between Manhattan and Queens had tracks installed on the lanes with conduits for Manhattan cars in addition to overhead wires. The conduit allowed them to run to Queens Plaza terminus without need for removing the plough, in later years the conduit was removed and only trolley wire remained. In the centre of Brussels some tram lines were fitted with conduits, the system was tried in the seaside resort of Blackpool, UK, but was soon abandoned as sand and saltwater entered the conduit and caused breakdowns and there was a problem with voltage drop. Some sections of track still had the conduit slot visible until the tramway was refurbished in 2012, washington, D. C. had a large network of conduit lines, to avoid wires. Some lines used overhead wires when they approached rural or suburban areas, the last such line ran to Cabin John, Maryland
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Chicago Transit Authority
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Chicago Transit Authority, also known as CTA, is the operator of mass transit in Chicago, Illinois and some of its surrounding suburbs, including the trains of the Chicago L and CTA bus service. In 1952, CTA purchased the assets of the Chicago Motor Coach Company, today, the CTA is one of the three service boards financially supported by the Regional Transportation Authority. The Chicago Transit Authority provides service to Chicago and 40 surrounding suburbs, the CTA provided a total of 532 million rides in 2011, a 3 percent increase over 2010 with ridership rising to levels not seen for 20 years. CTA operates 24 hours each day and on an average weekday provides 1.7 million rides on buses and it has approximately 1,800 buses that operate over 140 routes traveling along 2,230 route miles. Buses provide about one million trips a day and serve more than 12,000 posted bus stops in 10 suburbs. The Chicago Transit Authoritys 1,450 train cars operate eight routes and 222 miles of track. Its trains provide about 750,000 customer trips each weekday and serve 144 stations in Chicago and seven suburbs. Currently, the CTA operates within Chicago and the suburbs of Forest Park, Evanston, Skokie, Oak Park, Summit, Cicero, Berwyn, North Riverside, Rosemont. The CTA accepts payment with a Ventra card, a single-ride or 1-day Ventra disposable ticket, contactless credit or debit card, children under seven can ride free with a fare-paying rider, 3-child limit. Only buses allow riders to pay with cash, the bus fare is $2, the L fare is $2.25, and no cash transfers are available. The CTA no longer sells Transit Cards, all remaining Transit Cards must have been used by July 1,2014. In its place CTA has adopted the Ventra Card system, the Ventra Card can be purchased online, at any Ventra machine at CTA stations, and at authorized retailers. Ventra is a fare payment system for the Chicago Transit Authority and Pace that replaced the Chicago Card. Ventra launched in August 2013, with a full system transition slated for July 1,2014, Ventra is operated by Cubic Transportation Systems. Riders can pay a quarter for up to two transfers within two hours, the Chicago Transit Authority produced a monthly television show, Connections, from May 2003 through December 2011. The show was hosted by Dale Rivera, Jeanne Sparrow, Connections was broadcast on City of Chicago Public-access television cable TV channels 23 &49, as well as on Comcasts CN100 in the Chicago media market, including areas of Michigan and Indiana. Connections featured news and information about the CTA and services it provides, individual segments from Connections are available on CTAs YouTube channel. The majority of train stations CTA operates have elevators or ramps to access for customers with disabilities
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Chicago "L"
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The Chicago L is the rapid transit system serving the city of Chicago and some of its surrounding suburbs in the U. S. state of Illinois. It is operated by the Chicago Transit Authority, Chicagos L provides 24-hour service on some portions of its network, being one of only five rapid transit systems in the United States to do so. The oldest sections of the Chicago L started operations in 1892, making it the second oldest rapid transit system in the Americas, the L has been credited with fostering the growth of Chicagos dense city core that is one of the citys distinguishing features. The L consists of eight rapid transit lines laid out in a spoke–hub distribution paradigm focusing transit towards the Loop. Although the L gained its name because large parts of the system are elevated, portions of the network are also in subway tunnels, at grade level, or open cut. In 2014, the L had an average of 752,734 passenger boardings each weekday,486,267 each Saturday, over the next year service was extended to 63rd Street and Stony Island Avenue, then the Transportation Building of the Worlds Columbian Exposition in Jackson Park. In 1893, trains running on the Lake Street Elevated Railroad and in 1895 on the Metropolitan West Side Elevated, which had lines to Douglas Park, Garfield Park, Humboldt Park. Two years later the South Side L introduced multiple-unit control, in which the operator can control all the cars in a train. Electrification and MU control remain standard features of most of the rapid transit systems. A drawback of early L service was none of the lines entered the central business district. The Union Loop opened in 1897 and greatly increased the rapid transit systems convenience, insull instituted many improvements, including free transfers and through routing, although he did not formally combine the original firms into the Chicago Rapid Transit Company until 1924. The construction of the Subway created the necessity to tunnel under the Chicago River, the State Street Subway opened on October 17,1943, the Dearborn Subway, on which work had been suspended during World War II, opened on February 25,1951. The subways were constructed with a purpose of serving as bomb shelters. The subways bypassed a number of curves and circuitous routings on the original elevated lines. In 1947, the Chicago Transit Authority acquired the assets of the Chicago Rapid Transit Company and the Chicago Surface Lines, operator of the citys streetcars. Over the next few years CTA modernized the L, replacing wooden cars with new ones and closing lightly used branch lines and stations. Later, after assuming control of the L, the CTA introduced a service known as the A/B skip-stop service. Under this service, trains were designated as either A or B trains, a trains would only stop at A or AB stations, and B trains would only stop at B or AB stations
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Turboliner
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The Turboliners were a family of gas turbine trainsets built for Amtrak in the 1970s. They were among the first new equipment purchased by Amtrak to update its fleet with faster, the first batch, known as RTG, were built by the French firm ANF and entered service on multiple routes in the Midwestern United States in 1973. The new trains led to ridership increases wherever used, but the fixed consist proved a detriment as demand outstripped supply, the high cost of operating the trains led to their withdrawal from the Midwest in 1981. The second batch, known as RTL, were of a design but manufactured by Rohr Industries. These entered service on the Empire Corridor in the state of New York in 1976, the RTLs remained in service there through the 1990s, supplemented by several rebuilt RTGs. In the late 1990s and early 2000s, New York and Amtrak partnered to rebuild the RTLs for high-speed service, this failed. After the settlement of issues, New York sold the remaining trainsets for scrap in 2012. Amtrak assumed control of almost all private sector intercity passenger service in the United States on May 1,1971. Amtrak retained approximately 184 of the 440 trains which had run the day before, to operate these trains, Amtrak inherited a fleet of 300 locomotives and 1190 passenger cars, most of which dated from the 1940s–1950s. Amtrak acquired the Turboliners with multiple goals in mind, Amtrak also hoped that introducing new equipment would generate favorable publicity. Two years into its existence, Amtrak was fighting the perception that it was making changes to hand-me-down equipment. New gas turbine trainsets could change that perception, the late 1960s and early 1970s saw several countries experimenting with gas turbine trains. The UAC TurboTrain had been in service in the United States and Canada since 1968. British Rail began testing the APT-E in 1972, for a variety of reasons, the RTG model was an Americanized version of the French ANF T2000 RTG Turbotrain. The RTGs used European-style couplers between their cars, because they were built in France by ANF for French railways, another change was the installation of top-mounted Nathan P1234A5 horns, a variation of the standard Nathan P5. Amtrak obtained a permanent waiver from the Federal Railroad Administration which exempted the RTGs from the strength requirement of 800,000 pounds. The RTGs met a standard set by the International Union of Railways. Each trainset consisted of two cars, two coaches and a bar/grill
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Pennsylvania Station (New York City)
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Pennsylvania Station, also known as New York Penn Station or Penn Station, is the main intercity railroad station in New York City. Serving more than 600,000 commuter rail and Amtrak passengers a day, Penn Station is in the midtown area of Manhattan, close to Herald Square, the Empire State Building, Koreatown, and the Macys department store. Entirely underground, it sits beneath Madison Square Garden, between Seventh Avenue and Eighth Avenue and between 31st and 34th Streets, Penn Station has 21 tracks fed by seven tunnels. It is at the center of the Northeast Corridor, a rail line that connects New York City with Boston, Philadelphia, Washington, D. C. Intercity trains are operated by Amtrak, which owns the station, while rail services are operated by the Long Island Rail Road. Connections are available within the complex to the New York City Subway, additionally, if reopened, the old Hilton Corridor would recreate an indoor connection with Port Authority Trans-Hudson trains. The original Pennsylvania Station was built from 1901-1910 by the Pennsylvania Railroad, after a decline in passenger usage during the 1950s, the original station was demolished and reconstructed from 1963 to 1969, resulting in the current station. Pennsylvania Station is named for the Pennsylvania Railroad, its builder and original tenant, the current facility is the substantially remodeled underground remnant of a significantly more ornate station building designed by McKim, Mead, and White and completed in 1910. The original Pennsylvania Station was considered a masterpiece of the Beaux-Arts style, the station was moved fully underground, beneath the newly constructed Pennsylvania Plaza complex and Madison Square Garden arena completed in 1968. Until the early 20th century, the PRRs rail network terminated on the side of the Hudson River at Exchange Place in Jersey City. Manhattan-bound passengers boarded ferries to cross the Hudson River for the stretch of their journey. The rival New York Central Railroads line ran down Manhattan from the north under Park Avenue, the development of the electric locomotive at the turn of the 20th century made a tunnel feasible. The station would sit in Manhattans Tenderloin district, a historical district known for its corruption and prostitution. Beginning in June 1903, the two single-track North River Tunnels were bored from the west under the Hudson River. Electrification was initially 600 volts DC–third rail, and later changed to 11,000 volts AC–overhead catenary when electrification of PRRs mainline was extended to Washington, D. C. in the early 1930s. The same tube, with an inscription indicating that it had displayed at the Exposition, was later installed under water. Construction was completed on the Hudson River tunnels on October 9,1906, meanwhile, ground was broken for Pennsylvania Station on May 1,1904. Along with Long Island Rail Road trains, Penn Station saw trains of the New Haven and the Lehigh Valley Railroads
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Bumper cars
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They are also known as bumping cars and dashing cars. The inventor was Victor Levand, who worked for G. E, power is commonly supplied by one of two methods, The oldest and most common method uses a conductive floor and ceiling, each with a separate power polarity. Contacts under the vehicle touch the floor while a pole-mounted contact touches the ceiling, forming a complete circuit, a newer method uses alternating strips of metal across the floor separated by insulating spacers, and no ceiling grid. The alternating strips carry the current, and the cars are large enough so that the vehicle body can always cover at least two strips at any one time. The bumper cars on the Quantum-class cruise ships run on batteries and this avoids the conductive floor/ceiling of the traditional bumper cars setup, as the SeaPlex venue is to be readily convertible from a bumper cars ride to a multipurpose gym. The disadvantage is that these ships bumper cars take several hours to recharge their batteries, the metal floor is usually set up as a rectangular or oval track, and graphite is sprinkled on the floor to decrease friction. A rubber bumper surrounds each vehicle, and drivers ram each other as they travel, the controls are usually an accelerator and a steering wheel. The cars can be made to go backwards by turning the steering wheel far enough in either direction, although the idea of the ride is to bump other cars, safety-conscious owners sometimes put up signs reading This way around and No bumping. Depending on the level of enforcement by operators, these rules are often ignored by bumper car riders, especially younger children and teenagers. During their heyday, from the late 1920s to 1950s, two major US bumper cars brands were Dodgem by Max and Harold Stoehrer and the Lusse Brothers Auto-Skooter by. The current largest bumper cars floor is located at Six Flags Great America in Gurnee, Illinois, the ride is 51 feet,9 inches by 124 feet 9 inches or a total of 6,455 square feet. Six Flags Great Adventures Autobahn is the largest bumper car floor, bumper boats Current collector Electric vehicle Go-kart Witching Waves Bumping Down Memory Lane, The Lusse Legacy
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Siemens
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Siemens AG is a German conglomerate company headquartered in Berlin and Munich and the largest manufacturing and electronics company in Europe with branch offices abroad. The principal divisions of the company are Industry, Energy, Healthcare, and Infrastructure & Cities, the company is a component of the Euro Stoxx 50 stock market index. Siemens and its subsidiaries employ approximately 362,000 people worldwide, the von Siemens family remain the largest shareholder with a stake of 6. 9% percent. Siemens & Halske was founded by Werner von Siemens and Johann Georg Halske on 12 October 1847, based on the telegraph, their invention used a needle to point to the sequence of letters, instead of using Morse code. The company, then called Telegraphen-Bauanstalt von Siemens & Halske, opened its first workshop on 12 October, in 1848, the company built the first long-distance telegraph line in Europe,500 km from Berlin to Frankfurt am Main. In 1850, the younger brother, Carl Wilhelm Siemens, later Sir William Siemens. The London agency became an office in 1858. In the 1850s, the company was involved in building long distance telegraph networks in Russia, in 1855, a company branch headed by another brother, Carl Heinrich von Siemens, opened in St Petersburg, Russia. In 1867, Siemens completed the monumental Indo-European telegraph line, in 1867, Werner von Siemens described a dynamo without permanent magnets. A similar system was independently invented by Charles Wheatstone. In 1881, a Siemens AC Alternator driven by a watermill was used to power the worlds first electric lighting in the town of Godalming. The company continued to grow and diversified into electric trains and light bulbs, in 1890, the founder retired and left running the company to his brother Carl and sons Arnold and Wilhelm. In 1887, it opened its first office in Japan, Siemens & Halske was incorporated in 1897, and then merged parts of its activities with Schuckert & Co. Nuremberg in 1903 to become Siemens-Schuckert, in 1907, Siemens had 34,324 employees and was the seventh-largest company in the German empire by number of employees. In 1919, S & H and two companies jointly formed the Osram lightbulb company. During the 1920s and 1930s, S & H started to manufacture radios, television sets, in the 1920s, Siemens constructed the Ardnacrusha Hydro Power station on the River Shannon in the then Irish Free State, and it was a world first for its design. The company is remembered for its desire to raise the wages of its workers only to be overruled by the Cumann na nGaedheal government. Siemens exploited the forced labour of deported people in extermination camps, the company owned a plant in Auschwitz concentration camp
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Bus stop
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A bus stop is a designated place where buses stop for passengers to board or alight from a bus. These are normally positioned on the highway and are distinct from off-highway facilities such as bus stations, the construction of bus stops tends to reflect the level of usage. Stops at busy locations may have shelters, seating, and possibly electronic passenger information systems, less busy stops may use a simple pole, Bus stops may be clustered together into transport hubs allowing interchange between routes from nearby stops and with other public transport modes. Certain stops may be restricted to discharge/set-down only or pick-up only, some stops may be designated as timing points, and if the vehicle is ahead of schedule it will wait there to ensure correct synchronization with the timetable. In dense urban areas where bus volumes are high, skip-stops are sometimes used to increase efficiency, fare stages may also be defined by the location of certain stops in distance or zone-based fare collection systems. Sunday stops are close to a church and used only on Sundays, the first ever recorded bus stop was in Bishops Stortford and was believed to be constructed in 1890, linking Bishops Stortford to the town of Colchester. Bus stop infrastructure ranges from a pole and sign, to a rudimentary shelter. The usual minimum is a pole mounted flag with suitable name/symbol, Bus stop shelters may have a full or partial roof, supported by a two, three or four sided construction. The construction may feature advertising, from simple posters, to complex illuminated, some installations have also included interactive advertising. The stop may include separate street furniture such as a bench, lighting, individual bus stops may simply be placed on the sidewalk next to the roadway, although they can also be placed to facilitate use of a busway. More complex installations can include construction of a bus turnout or a bus bulb, for traffic management reasons, several bus stops may be grouped together to facilitate easy transfer between routes. These may be arranged in a row along the street. Groups of bus stops may be integral to transportation hubs, with extra facilities such as a waiting room or ticket office, outside groupings of bus stops can be classed as a rudimentary bus station. In certain areas, the area of road next the bus stop may be specially marked, often, car drivers can be unaware of the legal implications of stopping or parking in a bus-stop. In bus rapid transit systems, bus stops may be more elaborate than street bus stops and these may have enclosed areas to allow off-bus fare collection for rapid boarding, and be spaced further apart like tram stops. Bus stops on a bus transit line may also have a more complex construction allowing level boarding platforms. Most bus stops are identified with a sign attached to a pole or light standard. Some stops are plastic strips strapped on to poles and others involve a sign attached to a bus shelter, the signs are often identified with a picture of a bus and/or with the words bus stop
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Traction power network
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A traction network or traction power network is an electricity grid for the supply of electrified rail networks. In these areas there are no traction current networks, separate power for traction apart from industrial power always has historic roots. There is no reason today to apply different frequencies or current types than for transmission, however, the advantage with DC traction was the easier transmission with single copper wires to the feeder points. The advantage with AC traction is the transmission over long distances to the feeder points. Beyond these parameters and securing former investment, no evidence exists to stay with different current schemes in networks, dedicated traction current lines are used when railways are supplied with low-frequency alternating current. The traction current supply line is connected to substations along the line of the railway and is run separately from the overhead catenary wire from which the locomotives are fed. It is also possible to lay out the current supply on special cross beams right on the overhead wire pylons above the catenary wire. In densely populated areas, there are pylons which carry circuits for traction current and for three-phase alternating current for general power. Such lines are found where right of ways are rare, in particular the parallel route of 110 kV and 220 kV three-phase AC is common. The Mariazeller railway in Lower Austria operates on single phase AC at a 25 Hz utility frequency, the railway has its own traction current lines with an operating voltage of 27 kV. These lines are mounted on the pylons of the overhead wire over the catenary wire, in Germany, single conductors are usually used for traction current lines but, for the ICE train, two bundle conductors are used. Unlike in Western Germany, there are no dedicated power plants for railway electricity, all power comes from general electricity suppliers. Although in this there is, in principle, no requirement for traction power lines. In Norway, there is a small 55 kV single phase AC network for power supply of trains in the South, a further power station, at Kjofossen feeds single phase AC directly in the overhead wire. In Denmark and Finland,50 Hz is used for the main lines, as such, much simpler equipment than in Sweden and Norway is needed for conversion. In the Republic of South Africa there are extensive AC and DC traction schemes, electrification in Natal was stimulated by the takeover of the South African Railways system by the Electricity Supply Commission based on the Colenso power station. In the United Kingdom, the Network Rail 750 V DC electrification system in the southeast of England is supplied power from an extensive 33 kV power distribution network. This is typically the case in the German-speaking countries of Europe, for example,16.7 Hz AC is used in Germany, Austria and Switzerland
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Traction substation
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Rotary converters were also used, especially where the desired output was DC current from an AC source. In the 1920s, DC was derived using electronic valves, traction current converter plants are either decentralized or centralized. A list of current systems for rail traction provides further detail
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Power car
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The first of these types of vehicle is closely related to the locomotive. What differentiates the locomotive and the first type of car is their construction or use. A locomotive can be separated from its train and does nothing but provide propulsion. On the other hand, a car of the first type is frequently an integral part of its train. Nearly all high speed trains use power cars, frequently at both ends, an example of these are the Acela trainsets in use by Amtrak, which are built by Bombardier in Canada using technology licensed from Frances Alstom. The twenty Acela trainsets operate between Washington, D. C. and Boston, Massachusetts, each trainset consists of six passenger cars and two power cars. Another traditional example would be the older Intercity 125, made for and used by British Rail and several subsequent privatised bodies like Great Western Railway. Multiple units usually have a mix of cars and trailers, often with one of each in a pair which can be coupled to other pairs to form a larger train. New Zealand FP class electric multiple unit
36.
Electro-diesel locomotive
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An electro-diesel locomotive is powered either from an electricity supply or by using the onboard diesel engine. For the most part, these locomotives are built to serve regional and they may be designed or adapted mainly for electric use, mainly for diesel use or to work well as either electric or diesel. This is effectively an electric locomotive with a small auxiliary diesel prime mover intended only for low-speed or short-distance operation. Some of these, such as the British Rail Class 74, were converted from electric locomotives, the Southern Region of British Railways used these locomotives to cross non-electrified gaps and to haul boat trains that used tramways at the ports of Southampton and Weymouth. For economy, the engine and its generator are considerably smaller than the electric capacity. The Southern types were of 1,600 hp or Type 3 rating as electrics, later classes had as much as 2,500 hp on electric power, but still the same diesel engines. Despite this large difference, their comparable tractive efforts were much closer and so they could start and work equally heavy trains as diesels and this is effectively a diesel locomotive with auxiliary electric motors, usually operating from 750 V DC third rail where non-electric traction is banned. Once out of the tunnels, the engines are started and operation is as a diesel locomotive. With modern electronics, it is easier to construct an electro-diesel locomotive or multiple-unit which is equally at home running at high speeds both under the wires and under diesel power. They may also be used on long routes to take advantage of shorter sections of electrified main lines. Bombardier has built dual-mode variants of its AGC series for the French operator SNCF, voith Futura, a concept locomotive rebuilt from DB240002. Bombardier TRAXX Last Mile Diesel, mainly electric, orders signed 2010, to be delivered probably 2012. Five Electro-diesel versions of the Stadler Flirt have been ordered for service in the Valle dAosta region, PESA 111Ed Gama Marathon – mainly electric, with auxiliary diesel engine enabling last-mile operation on non-electrified tracks. Gama Marathon was first presented in 2012 at InnoTrans Berlin, the locomotive then underwent a series of tests with rail operators Lotos Kolej and PKP Intercity, after successful conclusion it was offered on the market. In July 2015 the Polish train-operating company Locomotiv bought the prototype, newag Dragon – version of this electric freight locomotive for the Freightliners Polish branch, Freightliner PL Sp. Z o. o. is equipped with diesel engine. These included, ED16, ED18, and TEU1 narrow gauge models OPE1, OPE2, NP1, PE2 and this series is a rebuild of FEVE1.000 Series locomotive. CAF Bitrac 3600,3000 V DC overhead wires, october 2007 order for 9 freight Co-Co locomotives
37.
Multi-system (rail)
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Multi-system trains provide continuous journeys over routes which are electrified using more than one system. Such conditions can occur where a train crosses national boundaries and each country has implemented a different electrification system, prior to 1945 there was little demand for multisystem locomotives in Europe.5 kV DC system both gave rise to new needs for multivoltage locomotives. Very high capital costs prevent or hinder the adoption of a railway electrification system. In India 1500 V DC and 25 kV50 Hz is used for main line trains, the 1500 V DC overhead system is used around Mumbai. The Mumbai region is the last bastion of 1500 V DC electrified lines on Indian Railways, the Western Railway route from Mumbai Central is now completely changed to 25 kV AC. The 25 kV AC system with lines is use throughout the rest of the country. The dual-voltage WCAM series locomotives haul intercity trains out of Mumbai DC suburban region, multi-system trains are found in metro use as well. The Kolkata Metro uses 750 V DC traction with a rail for delivering the electricity to the EMUs. The Kolkata trams use 550 V DC with overhead lines with underground conductors, the catenary is at a negative potential. The Delhi Metro uses 25 kV AC overhead lines on the ground-level and elevated routes, south Africa has 15 km of dual system track, both 3 kV DC and 25 kV AC. Electrification in the UK began in a piecemeal fashion, the earliest main line systems were divided between low voltage third rail and overhead systems. The third rail systems of this eventually gave rise to the 750 V DC system in the southern part of the UK. Starting with the West Coast Main Line electrification in the 1960s, in some areas with restricted clearances, particularly in urban areas in east London and on suburban routes around Glasgow,6.25 kV was used. A system known as Automatic Power Control was developed to allow trains to switch between the voltages whilst moving. This system proved unreliable and, with experience, it was found that less clearance was needed for 25 kV than had initially been allowed for. This allowed the 6.25 kV sections to be converted to 25 kV, with the last section, at the London end of the London Tilbury and Southend line, in the United States private companies undertook electrification independently, resulting in divergent systems. Multi-system operation continues to present day, the latter dates to the 1930s, when the Pennsylvania upgraded its electrified network from 650 V DC third rail. Double electrification Railway electric traction#Multi-system units M. M. Bakran, eckel, P. Eckert, H. Gambach, U
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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
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Railway electrification in Australia
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With the electrification of suburban networks, which began in 1919, a consistent electric rail traction standard was not adopted. Electrification began in Melbourne in 1919 using 1.5 kV DC, sydneys lines were electrified from 1926 using 1.5 kV DC, Brisbanes from 1979 using 25 kV AC, Perths from 1992 using 25 kV AC and Adelaides from 2014 using 25 kV AC. There has also been extensive non-urban electrification in Queensland using 25 kV AC,25 kV AC voltage has now become the international standard. Rail electrification in Sydney commenced in 1926—see Sydney electrification, from 1956 regional lines around Sydney to a radius of approximately 160 km were progressively electrified. Now the entire Sydney metropolitan area, and the intercity lines to Kiama, Lithgow and Newcastle are electrified, Electrification is at 1.5 kV DC. Queensland has the most extensive electrification in Australia and it includes the entire Brisbane metropolitan area, the North Coast Line to Rockhampton and the central Queensland coalfields. Electrification is at 25 kV AC, rail electrification in South Australia is limited to the Adelaide to Seaford and Adelaide to Tonsley lines. Adelaides first electric service commenced on 23 February 2014 Electrification is at 25 kV AC. There are no electrified lines in Tasmania. Australias first rail electrification was opened in Melbourne in 1919 - see Railways in Melbourne Electrification, Electrification is limited to the Melbourne metropolitan area. Previous electrification to Traralgon was removed in 1987, Electrification was subsequently truncated to Pakenham in Melbourne south east. Electrification is at 1.5 kV DC, the first line in Perth was electrified in 1991—see Transperth Trains. Electrification is at 25 kV AC, there are no electrified railway lines in the Northern Territory. Rail transport in Australia Churchman, Geoffrey B, railway Electrification in Australia and New Zealand
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Railway electrification in France
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There are 15,687 km of electrified railways in France. For historical reason there are two norms of electrification that coexist in France,1,500 V DC and 25 kV50 Hz AC, the electrification of the French railway network was made in four phases. First, at the start of the 20th century, there was a phase of testing, third rails and overhead lines were on trial in some lines in France, different voltages where tried. Afterwards, in the 1920s, the lines starting from Paris. After World War II and with the improvements in electronics, tests were made with 20 kV AC and subsequently with 25 kV AC in the Alps. Then the North and the East of France were electrified with 25 kV AC, the use of two norms of electrification was a huge problem for the SNCF up to the 1970s, because there was not much equipment able to run under both norms. Today, all electrical equipment ordered by the SNCF can use both 25 kV AC and 1,500 V DC
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