Information AboutTgv |
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: in Paris to western and southwestern destinations.]] The TGV ('''''t'''rain à '''g'''rande '''v'''itesse'', French for "high-speed train") is France 's High-speed Rail service, developed by GEC-Alsthom (now Alstom ) and SNCF , the French national Rail Operator , and operated primarily by SNCF. Following the inaugural TGV service between Paris and Lyon in 1981, the TGV network, centred on Paris, has expanded to connect cities across France. The success of the first line led to a rapid expansion of the service, with new lines built to the south, west and northeast of the country. Eager to share in the success of the French network, neighbouring countries such as Belgium , Italy and Switzerland built their own high-speed lines to connect with it. TGVs under other brand names also link to Germany and the Netherlands through the Thalys network, and to the United Kingdom through Eurostar . Several future lines are currently planned, including extensions within France and to surrounding countries. Towns such as Tours have become a part of this "TGV Commuter belt". TGVs travel at up to 320 Km/h (200 Mph ), which is made possible through the use of specially designed tracks, Laid Down without any sharp curves, and a range of features which make TGV trains suitable for high speed travel. These features include high-powered Electric Motor s, low axle weight, articulated carriages and In-cab Signalling which removes the need for drivers to see lineside Signal s at high speed. TGVs are manufactured primarily by Alstom, now often with the involvement of Bombardier . Except for a small series of TGVs used for Postal freight between Paris and Lyon, TGV is primarily a passenger service. Trains derived from TGV designs also operate in South Korea ( KTX ) and Spain ( AVE ). Travel by TGV has largely replaced air travel between connected cities, due to shorter commuting times (especially for trips taking less than three hours), reduced Check-in , security and boarding formalities, and the convenient location of Train Station s in the heart of cities. Furthermore, the TGV is a very safe mode of transport, with no recorded fatalities due to Accidents while running at high speed since operations began. HISTORY See Also: Development of the TGV The idea of the TGV was first proposed in the 1960s, after Japan began construction on the Shinkansen in 1959. At the time the French Government favoured new technologies, exploring the production of Hovercraft and Maglev trains such as Aérotrain . Simultaneously, SNCF began researching high-speed trains that would operate on conventional tracks. It was originally planned that the TGV, then standing for ''très grande vitesse'' (very high speed) or ''turbine grande vitesse'' (high speed turbine), would be propelled by Gas Turbine-electric Locomotive s. Gas Turbine s were selected for their small size, good Power-to-weight Ratio , and ability to deliver a high power output over an extended period of time. The first prototype, TGV 001 , was the only TGV constructed with this type of engine. However, following the sharp increase in the price of Oil during the 1973 Energy Crisis , gas turbines were deemed impractical and the project turned to locomotives powered by Electricity from Overhead Lines . The electricity was to be generated by France's new Nuclear Power Station s. However, TGV 001 was not a wasted prototype. Its gas-turbine powerplant was only one of many technologies required for high-speed rail travel. The TGV 001 platform also tested high-speed brakes, which were needed to dissipate the large amount of Kinetic Energy amassed by a train operating at high speed. Other technologies tested by the 001 included high-speed aerodynamics and signalling. The train was articulated, meaning that its two carriages shared a Bogie between them which allowed them to move freely with respect to one another. The prototype train reached 318 km/h (198 mph), which remains the world speed record for a non-electric train. The interior and exterior of TGV 001 were styled by British-born designer Jack Cooper, whose work formed the basis of all subsequent TGV design, including the distinctive nose shape of TGV power cars. Changing the specification of the TGV to incorporate electric traction required a significant design overhaul. The first fully electric prototype, nicknamed Zébulon, was completed in 1974, testing features such as innovative body-mounting of motors, Pantograph s, Suspension and Braking . Body mounting of motors allowed over 3 tonnes (2.95 tons) to be dropped from the weight of the power cars. The prototype travelled almost 1 000 000 km (621,000 miles) during testing. In 1976 the French Government fully funded the TGV project, and construction of the LGV Sud-Est, the first high-speed line (''ligne à '''g'''rande '''v'''itesse''), began shortly afterwards. The line was given the designation LN1, ''Ligne Nouvelle 1'' (New Line 1). , near Poitiers .]] After two pre-production trainsets had been rigorously tested and substantially modified, the first production version was delivered on 25 April 1980 . The TGV service opened to the public between Paris and Lyon on 27 September , 1981 . The initial target customers were businesspeople travelling between those two cities; as a mode of transport, the TGV was considerably faster than normal trains, Cars , or Airplanes . The trains soon became popular outside their initial target market; the public welcomed a fast and practical way to travel between cities. Since then, further LGVs have opened in France, including the LGV Atlantique (LN2) to Tours / Le Mans (construction began 1985, operation began 1989); the LGV Nord-Europe (LN3) to Calais and the Belgian border (construction began 1989, operation began 1993); the LGV Rhône-Alpes (LN4), extending the LGV Sud-Est to Valence (construction began 1990, operation began 1992); and the LGV Méditerranée (LN5) to Marseille (construction began 1996, operations began 2001). A line from Paris to Strasbourg , the LGV Est , is under construction. High-speed lines based on TGV technology have also been built in Belgium , the Netherlands and the United Kingdom to connect with the French network. Gare De Lyon .]] The Eurostar Service began operation in 1994, connecting Continental Europe to London via the Channel Tunnel . The line used the LGV Nord-Europe in France from the outset. The first phase of the British high-speed line, the Channel Tunnel Rail Link , was completed in 2003. The project, built with SNCF engineering expertise, is due for completion in 2007, by which time London-Brussels will take only 2 hours and London-Paris only 2h15. The TGV was not the world's first commercial high-speed service; the Japanese '' 2005 .. On 28 November 2003 the TGV carried its one-billionth passenger since the inception of the service in 1981, second in the world only to Shinkansen of Japan's 5 billion passengers reached in 2000. The two-billion mark is expected to be reached in 2010. TRACKS The TGV runs on dedicated tracks known as LGV (''ligne à grande vitesse'', "high-speed line"), allowing speeds of up to 320 Km/h (200 Mph ) in normal operation on the newest lines. Originally, LGV was defined as a line permitting speeds greater than 200 km/h (125 mph); this guideline was subsequently revised to permit speeds up to 250 km/h (155 mph). TGV trains can also run on conventional track (''lignes classiques''), albeit at the normal maximum safe speed for those lines, up to a maximum of 220 km/h (137 mph). This is an advantage that the TGV has over, for example, Magnetic Levitation Train s, as it means that TGVs can serve many more destinations and can use city-centre stations (as in Paris , Lyon , and Dijon ). They now serve around 200 destinations in France and abroad. LGV Construction is similar to normal railway lines, but with a few key differences. The Radii of curves are larger so that trains can travel them at higher speeds without increasing the Centrifugal Force felt by passengers. The radius of LGV curves has historically been greater than 4 Km (2.5 Mile s); new lines have minimum radii of 7 km (4 mi) to allow for future increases in speed. If used only for high-speed traffic, lines can incorporate steeper Grades . This facilitates the planning of LGV routes and reduces the cost of line construction. The considerable momentum of TGV trains at high speed means that they can climb steep slopes without greatly increasing their energy consumption. They can also coast on downward slopes, further increasing efficiency. The Paris-Sud-Est LGV features line grades of up to 3.5%, while on the German high-speed line between Cologne and Frankfurt they reach 4%. Track alignment is more precise than on normal railway lines, and Ballast is placed in a deeper than normal Profile , resulting in increased load-bearing capacity and track stability. LGV track is anchored by more Railway Sleeper s per kilometre than is usual in track construction, and all are made of concrete (either mono- or bi-blocs, the latter being when the sleeper consists of two separate blocks of concrete joined by a steel bar). Heavy rail (UIC 60) is used, and the rails themselves are more upright (1/40 as opposed to 1/20 on normal lines). Use of continuous welded rails in place of shorter, jointed rails means that the ride is comfortable at high speeds, without the usual "clickety-clack" vibrations induced by rail joints. Track must be at least Standard Gauge , 1,435 Mm (4 Ft 8½ In ), or Wide Gauge to allow speeds greater than 200 km/h (125 mph). Japan ese and Taiwan ese LGV networks are therefore isolated from the Narrow Gauge networks used for traditional rail in the two countries. On the Iberian Peninsula , however, which uses wide-gauge track on normal lines, standard gauge is used on LGVs so that they remain compatible with rail networks across the rest of Europe. If tunnels are required, their diameter must be greater than that required by the gauge of the trains travelling through them, especially at the entrances; this is to limit the effects of air pressure changes, which can be more problematic at the speeds reached by TGV trains. LGVs have a minimum speed limit. In other words, trains that are not capable of high speed generally may not use LGVs, which are reserved primarily for passenger trains. One reason for this limitation is that capacity is sharply reduced when trains of differing speeds are mixed. Passing freight and passenger trains also constitute a safety risk, as cargo on freight cars can be destabilized by the turbulent air that accompanies a high-speed TGV. Slower traffic is generally unable to use LGV track even during the midnight hours when no TGVs are running, because maintenance is performed on line infrastructure during these hours. The steep gradients common on TGV lines limit the weight of slow freight trains. Slower trains also mean that the maximum track cant (banking on curves) is limited, so for the same maximum speed a mixed-traffic LGV would need to be built with curves of even higher radius. Such track would be much more expensive and difficult to build and maintain. Because of expense, engineering difficulty and safety concerns, mixed-traffic LGV routes remain uncommon. However, certain stretches of less-used track are routinely mixed-traffic today, such as the Tours branch of the LGV Atlantique, and the planned Nîmes / Montpellier branch of the LGV Mediterranée. LGVs are all in Germany and 25 kV, 50/60 Hz everywhere else. The original Italian line between Rome and Florence , currently electrified at 3 kV DC, is to be converted to 25 kV 50 Hz AC to facilitate direct trains from France once new high-speed lines link it with the French network at Lyon via Turin . Catenary wires are kept at a higher tension than normal lines. This is because the Pantograph causes Oscillation s in the wires, and the Wave must travel faster than the train to avoid producing Standing Wave s which would cause the wires to break. This was a problem when rail speed record attempts were made in 1990; power wire tension had to be increased further still to accommodate train speeds of over 500 km/h (310 mph). While trains are on LGVs, only the rear pantograph is raised, avoiding amplification of the oscillations created by the front pantograph. The front power car is supplied by a cable running along the roof of the train. Eurostar trains are, however, long enough that oscillations are Damped sufficiently between the front and rear power cars that both pantographs can be safely raised. On ''lignes classiques'' (older, normal-speed rail lines) slower maximum speeds prevent oscillation problems, and both DC pantographs are raised. LGVs are fenced along their entire length to prevent animals and people from wandering onto the track. Level Crossing s are not permitted and bridges over the line are equipped with sensors to detect objects that fall onto the track. All LGV junctions are Grade-separated , i.e. the tracks are designed so that tracks crossing each other always use Flyovers or Tunnel s in order to avoid the need to cross in front of trains travelling in the opposite direction. Crossing over in front of other trains would require that service be halted in the opposite direction for extended periods of time, thus greatly reducing capacity. SIGNALLING See Also: LGV signalling Because TGV trains travel too fast for their operators to see and react to traditional lineside Signals , an automated system called TVM (''Transmission Voie-Machine'', or ''track to train transmission'') is used for signalling on LGVs. Information is transmitted to trains via electrical pulses sent through the rails, providing speed, target speed, and stop/go indications directly to the operator via dashboard-mounted instruments. This high degree of automation does not remove the train from driver control, though there are safeguards that can safely bring the train to a stop in the event of driver error. The line is divided into signal blocks of about 1500 M (1 Mile ), the boundaries of which are marked by blue boards printed with a yellow triangle. Dashboard instruments show the maximum permitted speed for a train's current block, as well as a target speed based on the profile of the line ahead. The maximum permitted speed is based on factors such as the proximity of trains ahead (with steadily decreasing maximum permitted speeds in blocks closer to the rear of the next train), Junction placement, speed restrictions, the top speed of the train and distance from the end of LGV track. As trains cannot usually stop within one signal block (which ranges from a few hundred metres to a few kilometres), drivers are alerted to slow down gradually several blocks before a required stop. Two versions of TVM signalling, TVM-430 and TVM-300, are in use on the LGV. TVM-430, a newer system, was first installed on the LGV Nord to the Channel Tunnel and Belgium, and supplies trains with more information than TVM-300. Among other benefits, TVM-430 allows a train's on-board computer system to generate a continuous speed control curve in the event of an emergency brake activation, effectively forcing the driver to reduce speed safely without releasing the brake. The signalling system is permissive; the driver of a train is permitted to proceed into an occupied block section without first obtaining authorization. Speed in this situation is limited to 30 km/h (19 mph; proceed with caution) and if speed exceeds 35 km/h (22 mph), the emergency brake is applied and the train stops. If the board marking the entrance to the block section is accompanied by a sign marked NF, the block section is not permissive, and the driver must obtain authorisation from the ''Poste d'Aiguillage et de Régulation'' (Signalling and Control Centre) before entering. Once a route is set, or the PAR has provided authorization, a white lamp above the board is lit to inform the driver. The driver then acknowledges the authorization using a button on the train's control panel. This disables the emergency braking which would otherwise occur when passing over the ground loop adjacent to the non-permissive board. When trains enter or leave LGVs from ''lignes classiques'', they pass over a ground loop which automatically switches the driver's dashboard indicators to the appropriate signalling system. For example, a train leaving the LGV onto a French ''ligne classique'' would have its TVM signalling system deactivated and its traditional KVB (''Contrôle Vitesse par Balise'', or ''beacon speed control'') system enabled. STATIONS One of the main advantages of TGV over other fast rail techologies such as Magnetic Levitation is that TGV trains can take advantage of existing infrastructure. This makes connecting city centres (such as Paris- Gare De Lyon to Lyon-Perrache ) with TGV a simple and inexpensive proposition; TGVs often use intra-city tracks and stations originally built with lower-speed trains in mind. |
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