Electric multiple unit
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 electric traction motors are incorporated within one or a number of the carriages. An EMU is formed of two or more semi-permanently coupled carriages, but electrically powered single-unit railcars are generally classed as EMUs; the great majority of EMUs are passenger trains, but versions exist for carrying parcels and mail. EMUs are popular on commuter and suburban rail networks around the world due to their fast acceleration and pollution-free operation. Being quieter than diesel multiple units and locomotive-hauled trains, EMUs can operate at night and more without disturbing nearby residents. In addition, tunnel design for EMU trains is simpler as no provision is needed for exhausting fumes, although retrofitting existing limited-clearance tunnels to accommodate the extra equipment needed to transmit electric power to the train can be difficult.
Multiple unit train control was first used in the 1890s. The Liverpool Overhead Railway opened in 1893 with two car electric multiple units, controllers in cabs at both ends directly controlling the traction current to motors on both cars; the multiple unit traction control system was developed by Frank Sprague and first applied and tested on the South Side Elevated Railroad in 1897. In 1895, derived from his company's invention and production of direct current elevator control systems, Frank Sprague invented a multiple unit controller for electric train operation; this accelerated the construction of electric traction railways and trolley systems worldwide. Each car of the train has its own traction motors: by means of motor control relays in each car energized by train-line wires from the front car all of the traction motors in the train are controlled in unison; the cars that form a complete EMU set can be separated by function into four types: power car, motor car, driving car, trailer car.
Each car can have more than one function, such as power-driving car. A power car carries the necessary equipment to draw power from the electrified infrastructure, such as pickup shoes for third rail systems and pantographs for overhead systems, transformers. Motor cars carry the traction motors to move the train, are combined with the power car to avoid high-voltage inter-car connections. Driving cars are similar to a cab car. An EMU will have two driving cars at its outer ends. Trailer cars are any cars that carry little or no traction or power related equipment, are similar to passenger cars in a locomotive-hauled train. On third rail systems the outer vehicles 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 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 and can only be split at maintenance facilities.
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. Each car has only one control cab, located at the outer end of the pair, saving space and expense over a cab at both ends of each car. Disadvantages include a loss of operational flexibility, as trains must be multiples of two cars, a failure on a single car could force removing both it and its partner from service; some of the more famous electric multiple units in the world are high-speed trains: the AGV in France, Italian Pendolino, Shinkansen in Japan, the China Railway High-speed in China and ICE 3 in Germany. The retired New York–Washington Metroliner service, first operated by the Pennsylvania Railroad and by Amtrak featured high-speed electric multiple-unit cars, see Budd Metroliner. EMUs powered by fuel cells are under development. If successful, this would avoid the need for third rail. An example is Alstom’s hydrogen-powered Coradia iLint.
The term hydrail has been coined for hydrogen-powered rail vehicles. Electro-diesel multiple unit Diesel multiple unit Battery electric multiple unit British electric multiple units
British Rail Class 458
The British Rail Class 458 is an electric multiple-unit passenger train built by Alstom at Washwood Heath between 1998 and 2002 for South West Trains. They were the first new fleet of trains to be delivered following the privatisation of British Rail; the fleet of 30 four-car trains was ordered in 1997, with the first train delivered in October 1998. The trains are maintained at Wimbledon depot, they form part of Alstom's Juniper family of trains, which includes Classes 334 and 460. Between 2013 and 2016, they were merged with the mechanically similar Class 460 fleet and reconfigured into 36 five-cars units, designated Class 458/5, to improve capacity; the trains are now used by South Western Railway. A tender for a fleet of thirty of these four-car trains was placed by South West Trains in November 1996 to create extra capacity and to replace some of the ageing Class 411 units, with a contract being signed between Alstom, the winner of the bid, it was reported that the tender took place to ease industry and political concern regarding the owner of South West Trains, Stagecoach Group's purchase of Porterbrook.
Deliveries of these units began in 1998. The units, numbered 458001-030, were delivered in SWT's mainline livery of white, with a blue band, red/orange'swish' at cab ends, they are the only Juniper EMUs. Each four car unit was formed from two outer driving motors, an intermediate trailer, an intermediate motor; the maximum speed when built was 100 miles per hour. The class suffered from major technical problems, such as leaky roofs and failing electronics; the gangways were designed on the presumption that the trains would be semi permanently coupled, with coupling and uncoupling taking thirty minutes, however in existing operations trains were coupled and uncoupled which had to be abandoned following the introduction of the new units. The protracted introduction led to South West Trains' decision to buy trains from the competing Siemens Desiro range in April 2001 for the replacement of the rest of the slam door fleet. In 2004, when the full fleet was in service, reliability was so poor that SWT planned to return them to the leasing company and replace them with new Class 450 Desiro trains.
At that time, the trains only managed an average of 4,300 miles between failures, compared with an average of 21,000 miles for a Class 450 Desiro and 50,000 miles for the previous slam-door trains. In September 2005, two units were transferred to Gatwick Express, but returned that year. By 2006, the reliability of the trains combined with the introduction of the new, more reliable British Rail Class 450 fleet meant that the trains had been withdrawn from regular service, with eight kept on standby. In July 2006, the Department for Transport refused to grant an further exemption from the Rail Vehicle Accessibility Regulations, resulting in modifications to the passenger information system being made, with new wider LEDs fitted within the existing housing; as part of Stagecoach's bid for the replacement South Western franchise, it was planned that the Class 442 stock would leave the franchise, with Class 444 stock internally cascaded to replace the units, that the Class 458s would return to service to maintain the overall fleet size.
It was speculated that this was due to Porterbrook being unable to find any other rail operators willing to lease the Class 458 trains, halving the rental costs. The Class 458s re-entered service with the 23 units having re-entered service in January, sufficient for the last Class 442 to be withdrawn on 24 January 2007. By February 2007, reliability had improved with the Class 458 fleet managing 17,800 miles between per 5-minute delays caused by failures, in contrast to expectations that the units' reliability would further suffer following their lengthy period in storage. In 2008–2010, Bournemouth Train Care Depot'refreshed' these EMUs. The'refresh' included adding CCTV, new seats and tables in first class, an internal repaint, Rail Vehicle Accessibility Regulations compliant lavatory, information display panels and door lights. In May 2010, two trains were in service with regenerative braking, the trial was a success with the rest of the fleet fitted by summer 2011. By the end of 2012, the fleet had achieved an average of 106,049 miles between failures, becoming the most reliable fleet in Britain and the first fleet to achieve a 6-figure rating.
As a result, the fleet was awarded a Modern Railways Golden Spanner award in the New Generation EMU category on 23 November 2012. South West Trains and Porterbrook merged the Class 458 trains with the mechanically similar Class 460 trains unused since September 2012, to form 5 coach trains. Six of the eight Class 460 trains lost three carriages in the process, leaving them as 5-car trains that were reconfigured as class 458/5 trains; the other two trains lost 6 carriages each, with the remaining 4 vehicles being decommissioned for spares. This £ 42m scheme was devised by owner of both fleets; the "new" 5-car sets will be designated Class 458/5 and coupled together to form 10-car trains to provide extra peak-time capacity on suburban services into Waterloo from the Hounslow and Windsor lines, using one of the five disused Waterloo International platforms, starting in 2014. The project was of SWT's aspiration to become a "10-car railway". Porterbrook signed the deal w
The Alstom Coradia is a family of diesel and electric multiple units for intercity and regional service, with variants operating in Europe and Algeria. The Coradia is a family of high-performance rolling stock, manufactured by Alstom Transport and offered in various configurations to suit the varying requirements of operators, it is available in an electric multiple unit configurations. The Coradia uses Alstom's own Onix igBT traction system, promoted as providing smooth acceleration and energy conservation facilities; the standard variants of the train are fitted with a regenerative braking system. The Coradia can be equipped with a variety of communication and signally systems, including national automatic train protection and European Train Control System; the Coradia is designed to offer a high degree of comfort for passengers. The design of the interior incorporates a modular philosophy; each seat can be equipped with electrical sockets, individual lighting, various audio and video systems.
The internal fittings can be redistributed, being mounted onto purpose-built slots. Amongst the options available for customisation are equipment such as vending machines, in-train ticketing dispensers, built-in internet provision; the Coradia range of regional trains includes the Coradia Duplex, Coradia Lint, Coradia Continental, Coradia Polyvalent and Coradia Nordic variants. Alstom has developed the Coradia Meridian for Trenitalia and other regional operators in Italy; the Coradia Continental an EMU operated as either three, five or six-carriage sets. The traction system is roof-mounted. Developed for German and other European markets, the Continental complies with the International Union of Railways loading gauge standard and is suitable for platform heights ranging from 550mm to 760mm; the Coradia Duplex train is a double-decker EMU operated in two to seven-carriage sets. The Duplex range includes two models, one developed and used for TER services in France as well as by Chemins de Fer Luxembourgeois, while the other is used in Sweden.
The Coradia Nordic is a wider body train developed for the large gauge standard used in Northern Europe, is available in configurations of four, five or six-carriage EMUs. To enable its use during the harsh winters common to Scandinavia, it can be operated at temperatures as low as -35°C, as well as being stored as low as -40°C. To free up space of passenger amenities as well as more spacious seating, the traction equipment for the Nordic is mounted upon the roof; the Coradia LINT designed by Linke-Hofmann-Busch before their acquisition by Alstom, is a diesel-powered light train, somewhat similar to the Siemens Desiro and Bombardier Talent. It is available in configurations of one and three-carriage sets; the propulsion system of the Lint features a diesel powerpack mounted upon the underframe of the carriage optimise the low-floor section. The design complies with the latest European environmental standards, it is used by a number of railways in Germany, the Netherlands, Denmark. As of 2018, the Coradia Polyvalent is the latest variant in the Coradia family.
It can operated at a maximum speed of 160 km/h in electric or bi-mode at voltages of 25 kV and 1,500 kV. The low integrated floor of the carriages provides improved accessibility and a high level of visibility to passengers; as a measure too restrict vibrations and noise levels, motorised bogies are placed at both ends of each carriage. The first British units entered service in 2001; the family is represented by two sub-families. The diesel-powered Coradia 1000 family consists of Class 175, a unit operating in Wales, Class 180 Adelante, a 125 mph high-speed train used by Grand Central and Hull Trains; the electric Coradia Juniper family now consists of the Class 334, the Class 458, but included the Class 460. During October 2009, Alstom received a €800 million order for 100 Coradia Polyvalents from French national railway operator SNCF. During March 2010, the company was awarded a follow-on €135 million contract for an additional 23 Coradia Polyvalents from SNCF. In May 2014, the Régiolis train was introduced by the ARF, SNCF and Alstom at the Vaugirard station in Paris.
As many as 182 Régiolis trains have been ordered by 12 French Regions. The Coradia Continental is in operation with several operators in Germany, it was introduced in 2002, has been ordered by Hamburger Hochbahn, DB Regio, Hessen State Railways. The Coradia LINT
Electric current collectors are used by trolleybuses, electric locomotives or EMUs to carry electrical power from overhead lines or electrical third rails to the electrical equipment of the vehicles. Those for overhead wires are roof-mounted devices, those for third rails are mounted on the bogies, they have one or more spring-loaded arms that press a collector or contact shoe against the rail or overhead wire. As the vehicle moves, the contact shoe slides along the wire or rail to draw the electricity needed to run the vehicle's motor; the current collector arms are electrically conductive but mounted insulated on the vehicle's roof, side or base. An insulated cable connects the collector with the transformer or motor; the steel rails of the tracks 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, bow collectors or trolley poles; the current collection device presses against the underside of the lowest wire of an overhead line system, called a contact wire.
Most overhead supply systems are either DC or single phase AC, using a single wire with return through the grounded running rails. Three phase AC systems use a pair of overhead wires, paired trolley poles. Electric railways with third rails, or fourth rails, in tunnels carry collector shoes projecting laterally, or vertically, from their bogies; the contact shoe may slide on the bottom or on the side. The side running contact shoe is used against the guide bars on rubber-tired metros. A vertical contact shoe is used on ground-level power supply systems, stud contact systems and fourth rail systems. A pair of contact shoes was used on underground current collection systems; the contact shoe on a stud contact system is called a ski collector. The ski collector moves vertically to accommodate slight variations in the height of the studs. Contact shoes may be used on overhead conductor rails, on guide bars or on trolley wires. Most railways use three rails. TRUCK
Alstom Coradia Juniper
The Coradia Juniper series is a family of electric multiple unit trains built by Alstom Transport Birmingham for use on the railway network in Great Britain. The family is related to the Coradia 1000 series of diesel multiple unit. There are two types in service with various TOCs, with a total of 76 units in service. All Class 460s are now converted to Class 458/5s for South Western Railway; the Class 334 is an EMU in service with Abellio ScotRail on the suburban network around Glasgow, including services to Edinburgh Waverley via Airdrie and Bathgate on the North Clyde Line. Class 334 trains are powered using overhead wires at 25 kV AC. A total of 40 three car units are in use, of which 38 were delivered from Alstom trains in 1999, although due to teething problems, two extra were ordered and they did not enter service until 2001; the Class 458 is operated by South Western Railway on services from London Waterloo to Reading, Windsor & Eton Riverside, circular metro routes from Waterloo via Richmond and Hounslow.
As with all electrically powered trains on the former Southern Region, the Class 458 units are powered using third rail at 750 V DC current. A total of thirty 4-car units were built, with deliveries beginning in 1998, with the full complement in service by 2004. However, they suffered from leaky roofs and failing electronics and were therefore stored from 2004 to late 2005, being replaced by more Class 450 units on the routes they operated. For a brief period, they were subleased to Gatwick Express, but were never used on Gatwick Express Services. In 2013, former operator South West Trains and Porterbrook began the process of creating a new, 36-strong fleet of 5-car trains by reforming and rebuilding the vehicles from the Class 458 and Class 460 fleets; the new units have been renumbered as the Class 458/5. They entered service in March 2014. Work included complete reconstruction of cabs and gangways, as well as changes to the passenger areas; the units are being repainted into the same livery as the Class 450 units.
This process was completed in 2016. The original 30 ex-Class 458/0 units are numbered 458501-458530, are distinguishable from the ex-Class 460 stock by noting the different ribbon-glazed windows on ex-Class 460 units, different door window sizes and the lack of a pantograph recess on ex-Class 460 units; this means that if future conversion to OHLE is required for this fleet, the process will be much simpler on 458501-458530 than 458531-458536. All units are now in South Western Railway - branded South West Trains livery, are due to be replaced on all South Western Railway routes by new Class 701 units from 2019-2020; the Class 460 electric multiple units were built for use on the dedicated Gatwick Express airport service to London Victoria. The units were delivered between 2000 and 2001 and like the similar Class 458 they were powered using 750 V DC current on the third rail; the fleet consisted of 8 units in total numbered 460001-008, each formed of 8 vehicles. Following their removal from the Gatwick Express franchise in September 2012 a decision was made to reform and merge the Class 460s with the Class 458 vehicles in order to form 36 x 5-car trains to boost capacity on the South West Trains network.
The first two of the 5-car sets were delivered in October 2013. Passenger service had started in March 2014
Edinburgh Waverley railway station
Edinburgh Waverley railway station is the principal station serving Edinburgh, the capital city of Scotland. It is the second busiest station in Scotland, after Glasgow Central, it is the northern terminus of the East Coast Main Line, 393 miles 13 chains from London King's Cross, although some trains operated by London North Eastern Railway continue to other Scottish destinations beyond Edinburgh. Services to and from Edinburgh Waverley are operated by Abellio ScotRail, including four routes to Glasgow, the Fife Circle, the reopened Borders Railway and services to Stirling/Dunblane/Alloa/North Berwick/Dunbar; the station is the terminus of the Edinburgh leg of the West Coast Main Line served by Virgin Trains and TransPennine Express. Long distance inter-city trains to England are operated by CrossCountry to destinations such as York, Sheffield, Birmingham New Street, Bristol Temple Meads, Exeter St Davids and Plymouth. Waverley station is situated in a steep, narrow valley between the medieval Old Town and the 18th century New Town.
Princes Street, the premier shopping street, runs close to its north side. The valley is bridged by the North Bridge, rebuilt in 1897 as a three-span iron and steel bridge, on huge sandstone piers; this passes high above the station's central section, directly over the central booking hall. Waverley Bridge lies to the west side of the station and it is this road which, by means of ramps afforded vehicular access to the station and still provides two of the six pedestrian entrances to the station; the valley to the west the site of the Nor Loch, is the public parkland of Princes Street Gardens. Edinburgh's Old Town, perched on a steep-sided sloping ridge, was bounded on the north by a valley in which the Nor Loch had been formed. In the 1750s overcrowding led to proposals to link across this valley to allow development to the north; the "noxious lake" was to be narrowed into "a canal of running water", with a bridge formed across the east end of the loch adjacent to the physic garden. This link was built from 1766 as the North Bridge and at the same time plans for the New Town began development to the north, with Princes Street to get unobstructed views south over sloping gardens and the proposed canal.
The loch was drained. In 1770 a coachbuilder began work on properties feued at the corner between the bridge and Princes Street, feuers on the other side of the street objected to this construction blocking their views to the south. A series of court cases ended with the decision that the buildings nearing completion could stay to the west of that some workshops would be allowed below the level of Princes Street, further west a park would be "kept and preserved in perpetuity as pleasure ground" in what became Princes Street Gardens. In the mid 1830s proposals for a railway from Glasgow running along the gardens to a station at the North Bridge were set out in a prospectus with assurances that the trains would be concealed from view, smoke from them "would scarcely be seen". An association of "Princes Street Proprietors" who had feued houses in the street, had spent large sums turning the "filthy and offensive bog" of the Nor Loch into quiet gardens opposed the railway and in late 1836 put forward their case against the Act of Parliament for the railway.
The Edinburgh and Glasgow Railway opened in 1842 with its terminus at Haymarket railway station, stopping short of Princes Street. In the Railway Mania of the 1840s, the railway sought another Act of Parliament allowing access along the gardens, at the same time two other railways proposed terminus stations at the North Bridge site. By several of the Princes Street properties were shops or hotels with an interest in development, agreement was reached in 1844 on walls and embankments to conceal the Edinburgh and Glasgow railway line in a cutting, with compensation of £2,000 for the proprietors; the North Bridge station was opened on 22 June 1846 by the North British Railway as the terminus for its line from Berwick-upon-Tweed. The Edinburgh and Glasgow Railway's General station opened on 17 May 1847, on the same day as the Canal Street station of the Edinburgh and Newhaven Railway, serving Leith and Granton via a long rope-hauled tunnel under the New Town; the collective name "Waverley", after the Waverley Novels by Sir Walter Scott, was used for the three from around 1854 when the through'Waverley' route to Carlisle opened.
Canal Street station was known as Edinburgh Princes Street, not to be confused with the Caledonian Railway railway station built at the West End, named Princes Street station from 1870. In 1868 the North British Railway acquired the stations of its rivals, demolished all three, closed the Scotland Street tunnel to Canal Street; the present Victorian station was built on the site, extended in the late 19th century. Waverley has been in continual use since, under the auspices of the North British, the LNER, British Railways and latterly Network Rail. From its opening in its current form by the eastward tunnelled extension from Haymarket, Waverley has been the principal railway station in Edinburgh. From 1870 to 1965 the city had a second major station, Princes Street, operated by the rival Caledonian Railway, but this was never as important as Waverley; as at other large railway stations of the Victorian and Edwardian eras, the railway company constructed a grand station hotel beside their station.
The North British Hotel, adjacent to the station at the corner between Princes Street and North Bridge (on the site of the c
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 line. It is a common type of current collector. A single or double 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 and drawings. The pantograph, with a low-friction, replaceable graphite contact strip or'shoe' to minimise lateral stress on the contact wire, 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 RailroadThe familiar diamond-shaped roller pantograph was invented by John Q. Brown of the Key System shops for their commuter trains which 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 pantograph was an improvement on the simple trolley pole, which prevailed up to that time because the pantograph allows an electric-rail vehicle to travel at much higher speeds without losing contact with the overhead lines, e.g. due to dewirement of the trolley pole. Notwithstanding this, trolley pole current collection was used at up to 90 mph on the Electroliner vehicles of the Chicago North Shore and Milwaukee Railroad known as the North Shore Line; the most common type of pantograph today is the so-called half-pantograph, which evolved to provide a more compact and responsive single-arm design at high speeds as trains got faster. Louis Faiveley invented this type of pantograph in 1955; the half-pantograph can be seen in use on everything from fast trains to low-speed urban tram systems. The design operates with equal efficiency in either direction of motion, as demonstrated by the Swiss and Austrian railways whose newest high performance locomotives, the Re 460 and Taurus, operate with them set in the opposite direction.
The geometry and shape of the pantographs are specified by the EN 50367/IEC 60486 - Railway applications - Current collection systems - Technical criteria for the interaction between pantograph and overhead line. The electric transmission system for modern electric rail systems consists of an upper, weight-carrying wire from, suspended a contact wire; the pantograph is spring-loaded and pushes a contact shoe up against the underside of the contact wire to draw the current needed to run the train. The steel rails of the tracks act as the electrical return; as the train moves, the contact shoe slides along the wire and can set up standing waves in the wires which break the contact and degrade current collection. This means. Pantographs are the successor technology to trolley poles, which were used on early streetcar systems. Trolley poles are still used by trolleybuses, whose freedom of movement and need for a two-wire circuit makes pantographs impractical, some streetcar networks, such as the Toronto streetcar system, which have frequent turns sharp enough to require additional freedom of movement in their current collection to ensure unbroken contact.
However, many of these networks, including Toronto's, are undergoing upgrades to accommodate pantograph operation. Pantographs with overhead wires are now the dominant form of current collection for modern electric trains because, although more fragile than a third rail system, they allow the use of higher voltages. Pantographs are operated by compressed air from the vehicle's braking system, either to raise the unit and hold it against the conductor or, when springs are used to effect the extension, to lower it; 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 same air supply is used to "blow out" the electric arc when roof-mounted circuit breakers are used. Pantographs may have a double arm. Double-arm pantographs are heavier, requiring more power to raise and lower, but may be more fault-tolerant. On railways of the former USSR, the most used pantographs are those with a double arm, but since the late 1990s there have been some single-arm pantographs on Russian railways.
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. American streetcars use either trolley poles or single-arm pantographs. Most rapid transit systems are powered by a third rail, but some use pantographs ones that involve extensive above-ground running. Most hybrid metro-tram or'pre-metro' lines whose routes include tracks on city streets or in other publicly accessible areas, such as line 51 of the Amsterdam Metro, the MBTA Green Line, RTA Rapid Transit in Cleveland, Frankfurt am Main U-Bahn, San Francisco's Muni Metro, use overhead wire, as a standard third rail would obstruct street traffic and present too great a risk of electrocution. Among the various exceptions are several tram systems, such as the ones in Bordeaux, Angers and Dubai that use a proprietary underground system developed by Alstom, called APS, which only applies power to segments of track that are covered by the tram.
This system was designed to be used in the historic centre of Bordeaux because an overhead wire system would cause a visual intrusion. Similar systems that avoid overhead lines have been developed by Bombardier, AnsaldoBreda, CAF, and