TGV
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The TGV is France's train à grande vitesse; literally "high-speed train". Developed by Alstom and SNCF, and operated by SNCF, the French national railway company, it connects cities in France, especially Paris, and in some other neighbouring countries, such as Belgium and Switzerland. TGVs or trains derived from TGV design also operate in the Netherlands, Germany, South Korea, Spain, the United Kingdom, and the United States. TGV trains are manufactured primarily by Alstom, now often with the involvement of Bombardier.
The TGV is a passenger train, except for a small series of TGVs used for postal freight between Paris and Lyon, France.
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History
The idea of the TGV was first proposed in the 1960s. The first prototype, known as TGV 001, was powered by gas turbines and generated its own electricity from oil, but after the 1973 energy crisis and the consequent sharp rise in the price of oil this was deemed impractical.
The first fully electric prototype was completed in 1974, with the final version delivered in 1980 and the service opened to the public between Paris to Lyon on 27 September 1981. The initial target customers were businesspeople travelling between those two cities; the TGV was for them a faster solution than normal trains, cars, or airplanes. The client base soon expanded across the population, which welcomed a practical and fast way to travel between cities.
Since then, dedicated lines to Tours/Le Mans, Calais, Brussels and Marseille have opened. A line to Strasbourg is under construction, as are dedicated high-speed lines to Cologne and Amsterdam. Further extensions into Spain and Italy are planned for the future. A high-speed line to London from Folkestone (see Channel Tunnel Rail Link) is also under construction, using SNCF engineering expertise.
The TGV is not the world's first commercial high-speed service, as the Japanese Shinkansen connected Tokyo and Osaka from 1 October 1964, nearly 17 years before the first TGVs entered commercial operation.
The TGV is one of the fastest commercially operating conventional trains in the world, but it is the fastest in the world under test conditions: in 1990 it reached speeds of 515.3 km/h (320.2 mph) with a shortened train (two power cars and three passenger cars).
On the 28th November 2003 the TGV carried its billionth passenger since operations began in 1981. 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 in normal operation on the newest lines. Originally defined as a line permitting speeds greater than 200 km/h, this has now been increased to 250 km/h. TGV trains can also run on conventional tracks (lignes classiques), albeit at the normal maximum line speed for those lines, up to a maximum of 220 km/h. This is an advantage that the TGV has over, for example, magnetic levitation trains, as it means that TGVs can serve far more destinations and can use city-centre stations (for example in Paris, Lyon, and Dijon). They now serve around 200 destinations in France and abroad.
The LGVs are similar to normal railway lines, but there are key differences. The radii of curves are larger so that the trains can travel at higher speeds around them without increasing the centrifugal force felt by passengers. This radius is usually greater than 4km, but new lines have minimum radii of 7km to allow for future increases in speed.
If used only for high-speed traffic, lines can incorporate steeper gradients. This facilitates the planning of LGV routes and reduces the cost of construction. The momentum of TGV trains at high speed means that they can climb steep slopes without greatly increasing their energy consumption, and they can coast down. On the Paris-Sud-Est LGV there are gradients of 35‰ and on the German high-speed line between Cologne and Frankfurt they reach 40‰.
Track alignment is more precise. Ballast is built into a stronger profile. There are more sleepers per km and all are made of concrete (either mono- or biblocs, 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). 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 m) or wide gauge to allow speeds greater than 200 km/h. Japanese and Taiwanese LGV networks are therefore separated from the original narrow gauge networks. 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 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.
There is a minimum speed limit, that is to say trains which are not capable of high speed may not use LGVs, and their use is limited for the most part to passenger trains. Mixed traffic imposes severe restraints on the use of a high-speed line. Capacity reduces sharply if trains of differing speeds are on it. Freight trains and passenger trains passing also poses a risk due to the possible destabilisation of cargo caused by the air currents around the passing trains. Night use by slower traffic when TGVs are not running is also not possible. The line infrastructure is maintained at night so regular freight flows would not be viable. The steep gradients on TGV lines limit the weight of slow freight trains. Slower trains would also mean that the maximum track cant (banking on curves) would be limited, so for the same maximum speed LGVs would need to be built with curves of even higher radius. A mixed-traffic LGV would therefore be more expensive and difficult to plan to take account of the relief of land and obstacles. Mixed-traffic LGV lines are therefore limited only to a few certain stretches of less-used track, namely on the Tours branch of the LGV Atlantique, and on the planned Nimes/Montpellier branch of the LGV Mediterranée.
LGVs are all electrified. Apart from the constraints involved in refuelling and carrying fuel on board trains, diesel traction cannot produce the continuous thrust required for high-speed running. Apart from the Italian high-speed line between Rome and Florence, which is currently electrified at 3 kV DC (the same as the rest of the Italian network, although conversion to the European standard for LGVs is planned), LGVs are electrified at high voltage AC: 15 kV 16 2/3 Hz in Germany and Austria, and 25 kV 50/60 Hz everywhere else, including future Italian high-speed lines.
Catenary wires are kept at a higher tension than normal lines. This is because the pantograph causes oscillations in the wires, and the wave must travel faster than the train to avoid producing standing waves (high amplitude oscillations caused by the pantograph running under an already oscillating wire) which would cause the wires to break. This was a problem when attempting the rail speed record in 1990 when the tension had to be increased further still to accommodate train speeds of over 500 km/h. This also means that while trains are on LGVs, only the rear pantograph is raised, to avoid the rear pantograph amplifying oscillations created by the front pantograph. The front power car is supplied by a cable running along the roof. Eurostar trains are, however, long enough that oscillations are damped sufficiently between the front and rear power cars and both pantographs are raised. On lignes classiques this is not a problem due to the slower line speed, and both DC pantographs are raised.
LGVs are fenced along their entire length to avoid animals on the line. Level crossings are not permitted and bridges over the tracks are equipped with sensors to detect if anything has fallen onto the line.
LGV Signalling
The TVM (or Transmission Voie-Machine) system is used for signalling on LGVs. Information is transmitted to trains via electrical pulses through the rails, giving indications (speed, target speed, stop/go) directly to the train driver through dashboard-mounted visual indicators rather than lineside signals - trains are travelling too fast to be sure of seeing lineside signal aspects. Trains are under the driver's control, though there are safeguards against driver errors that can safely bring the train to a stop.
The line is divided into signal blocks, the boundaries of which are marked by blue boards with a yellow triangle. The indicators on the dashboard show the maximum permitted speed for the block where the train is and also a target speed based on the profile of the line. The maximum permitted speed is based on factors such as the location of trains ahead (with steadily decreasing maximum permitted speeds in blocks closer to the rear of the next train), junctions, speed restrictions, the maximum speed of the train and an approaching end of LGV. As trains cannot usually stop in the distance of one signal block (which varies between a few hundred metres and a few kilometres), drivers are alerted when there is a requirement to slow down gradually several blocks in advance.
Two types of signalling are in use on the LGV: TVM-300, the older system and TVM-430. TVM-430 was first installed on the LGV Nord to the Channel Tunnel and Belgium, and supplies trains with more information than the older system, allowing the on-board system to generate a continuous speed control curve in the event of an emergency brake activation, and force and guide the driver to control the speed without releasing the brake. However, drivers can always anticipate braking as they know the maximum authorized speed in the block in front of them as well as in the block which they are in from the signalling system.
The signalling system is permissive, i.e. 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 30km/h (proceed with caution) and if the speed exceeds 35 km/h, 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 authorization from the OCC prior to entering. Once a route is set, or the OCC 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 control panel This disables the emergency brake application 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 the KVM system used on the lignes classiques would be enabled.
TGV Stations
As mentioned above, one of the main advantages of TGV compared to other technologies such as maglev is that it can run on existing tracks and use existing stations, or stations shared with other types of trains. This means that it is easy to serve routes from city centre to city centre (say, Paris-Gare de Lyon to Lyon-Perrache) without having to build new tracks or stations inside cities. Building new stations in city centres can be expensive, usually involving either long tunnels or bridges so that the new route can pass through densely populated areas.
However, there has been a tendency to build new stations serving smaller locations in suburban areas or in the open countryside some miles away from the town, so as to be able to make a stop without incurring too great a time penalty. In some cases, such as the station serving Montceau-les-Mines and Le Creusot, the station was built in the middle between the two towns. Another example is the Haute Picardie station between Amiens and Saint-Quentin. This latter one was rather controversial, criticized in the press and by local government as too far from either town to be useful, and sited near a trunk road rather than a connecting railway line: it was often nicknamed la gare des betteraves, or 'beetroot station'.
A number of major new railway stations were built, some of which have been major architectural achievements in their own right. Avignon TGV station (left), opened in 2001, has won particular praise as one of the most remarkable stations on the network, with a spectacular 340m-long glazed roof that has led to the building being compared to a cathedral.
Rolling stock
TGV rolling stock differs from other types in that trains consist of semi-permanently coupled multiple units. Bogies are located between the carriages, supporting the carriages on either side, so that each carriage shares its bogies with the two adjacent to it. Locomotives at either end of the trains have their own bogies.
This design means that in the case of a derailment, the locomotive derails first and can move separately from the passenger carriages, which are more likely to stay upright and in line with the track. This is unlike normal trains which tend to split at the couplings and jacknife.
The disadvantage of the design is that it is difficult to split sets of carriages. The locomotives can be removed normally by uncoupling them, but to split the carriages requires the use of lifting equipment in maintenance depots which can lift an entire set at once. Once uncoupled, one of the carriage ends is left without a bogie at the split, so a bogie frame is required to hold it up.
SNCF operates a fleet of about 400 TGV trainsets. Six types of TGV or TGV derivative currently operate on the French network: TGV Sud-Est (passenger and La Poste varieties), TGV Atlantique, TGV Réseau/Thalys PBA, Eurostar, TGV Duplex and Thalys PBKA. A seventh type, TGV POS (Paris-Ostfrankreich-Suddeutschland, or Paris-Eastern France-Southern Germany), is currently being tested.
All TGVs are at least bi-current, that is to say they can operate under 25kV, 50Hz AC on newer lines, including LGVs and under 1,500V DC on older French lignes classiques, especially around Paris. Trains crossing the border into Germany, Switzerland, Belgium, the Netherlands and the United Kingdom must accommodate foreign voltages. This has led to the construction of tri-current or even quadri-current TGVs. All TGVs are equipped with two pairs of pantographs, two for AC use and two for DC use. When passing between areas of different supply voltage, marker boards are installed to remind the driver to lower the pantograph(s) and turn off power to the traction motors, adjust a switch on the dashboard to the appropriate system, and raise the pantograph(s) again, pantographs and pantograph height control being selected automatically depending on the voltage system selected. Once the train detects the correct supply to its transformers, an indicator lights and the driver can switch on power to the traction motors. The train coasts across the border between voltage sections while traction motor power is off.
TGV Sud-Est
The TGV Sud-Est fleet was built between 1978 and 1988 and operated the first TGV service from Paris to Lyon in 1981. Currently there are 107 passenger sets operating, of which nine are tri-current (including 15kV, 16 2/3 Hz AC for use in Switzerland) and the rest bi-current. There are also 7 bi-current half-sets without seats which carry mail for La Poste between Paris and Lyon. These are painted in a distinct yellow livery.
Each set is made up of two power cars and eight carriages (capacity 345 seats), including a powered bogie in each of the carriages adjacent to the power cars. They are 200m long and 2.81m wide. They weigh 385t with a power output of 6,450 kW under 25kV.
Originally the sets were built to run at 270 km/h but most were upgraded to 300 km/h during their mid-life refurbishment in preparation for the opening of the LGV Méditerranée. The few sets which still have a maximum speed of 270 km/h operate on routes which have a comparatively short distance on the lignes à grande vitesse, such as those to Switzerland via Dijon. SNCF did not consider it financially worthwhile to upgrade their speed for a marginal reduction in journey time.
TGV Atlantique
The TGV Atlantique fleet was built between 1988 and 1992. 105 bi-current sets were built for the opening of the LGV Atlantique and entry into service began in 1989. They are 237.5m long and 2.9m wide. They weigh 444t, and are made up of two power cars and ten carriages with a capacity of 485 seats. They were built from the outset with a maximum speed of 300 km/h with 8,800 kW total power under 25kV.
A modified set 325 set the world speed record in 1990 on the new LGV before its opening. Various modifications, such as improved aerodynamics, larger wheels and improved braking were made to enable speeds of over 500 km/h. The set was also reduced to two power cars and three carriages to improve the power-to-weight ratio, weighing 250t. Three carriages, including the bar carriage in the centre, is the minimum possible configuration because of the way the sets are articulated.
TGV Réseau
The first TGV Réseau sets entered service in 1993. 50 bi-current sets were ordered initially in 1990, supplemented by an order for 40 tri-current sets in 1992/1993. Ten of the tri-current sets carry the Thalys livery and are known as Thalys PBA (Paris-Brussels-Amsterdam) sets. The tri-current sets, as well as the standard French voltages, can operate under the Low Countries' and Italian 3kV DC supplies.
They are formed of two power cars (8,800 kW under 25kV - as TGV Atlantique) and eight carriages, giving a capacity of 377 seats. They have a top speed of 300 km/h. They are 200m long and are 2.81m wide. The bi-current sets weigh 383t, but due to axle-load restrictions in Belgium the tri-current sets have a series of modifications such as replacement of steel with aluminium and hollow axles to reduce the weight to under 17t per axle.
After complaints of uncomfortable pressure changes when entering tunnels at high speed on the LGV Atlantique, the Réseau sets are pressure sealed.
Eurostar
The Eurostar train is essentially a long TGV, modified for use in the United Kingdom and in the Channel Tunnel. In the UK, it is known under the TOPS classification system as a Class 373 Electric Multiple Unit. In planning stages, it was also known as the TransManche Super Train (Cross-channel Super Train). The trains were built by GEC-Alsthom (now Alstom) at its sites in La Rochelle (France), Belfort (France) and Washwood Heath (England), entering service in 1993.
Two types were built: the Three Capitals sets consist of two power cars and eighteen carriages, including two powered bogies; the North of London sets consist of two power cars and only fourteen carriages, again with two powered bogies. Full sets of both types consist of two identical half-sets which are not articulated in the middle, so that in case of emergency in the Channel Tunnel, one half can be uncoupled and leave the tunnel. Each half-set is numbered separately.
38 full sets, plus one spare power car, were ordered by the railway companies involved: 16 by SNCF, 4 by SNCB, and 18 by British Rail, of which seven were North of London sets. Upon privatisation of British Rail by the UK Government, the sets were bought by London & Continental Railways who named the subsidiary Eurostar (U.K.) Ltd., now managed by a consortium of companies made up of the National Express Group (40%), SNCF (35%), SNCB (15%) and British Airways (10%).
The Three Capitals sets operate at a maximum speed of 300 km/h, with the power cars supplying 12,240 kW of power. They are 394m long and have a capacity of 766 seats, weighing a total of 752t. The North of London sets have a capacity of 558 seats. All of the trains are at least tri-current and are able to operate on 25kV 50Hz AC (on LGVs, including the Channel Tunnel Rail Link, and on UK overhead electrified lines), 3kV DC (on lignes classiques in Belgium) and 750V DC on the UK Southern Region third rail network. The third rail system will become superfluous in 2007 when the second phase of the Channel Tunnel Rail Link is completed between London and the Channel Tunnel, as it uses 25kV 50Hz AC exclusively. Five of the Three Capitals sets owned by SNCF are quadri-current and are also able to operate on French lignes classiques at 1500V DC.
Three of the Three Capitals sets owned by SNCF are used for French domestic use and currently carry the silver and blue TGV livery. The North of London Eurostar sets have never seen international use but were originally intended to provide direct services from continental Europe to UK cities north of London, using the West Coast Main Line and the East Coast Main Line. These never came to fruition, however, and a few of the sets were leased to GNER for use on its White Rose service between London and Leeds, with two of them carrying GNER's dark blue livery, although the lease will be ending in December 2005.
TGV Duplex
The TGV Duplex was built to increase TGV capacity without increasing train length, or number of trains. Each carriage has two levels, with access doors at the lower level taking advantage of low French platforms. A staircase provides access to the upper level. This layout provides a capacity of 512 seats per set. On many routes they are operated in pairs, providing 1024 seats in a single train.
After a lengthy development process starting in 1988, they were built in two batches, thirty being built between 1995 and 1998, then a further thirty-four between 2000 and 2004. They weigh 386t and are 200m long, made up of two power cars and eight bi-level carriages. Extensive use of aluminium means that they do not weigh much more than the TGV Réseau sets they supplement. The bi-current power cars provide a total power of 8,800 kW, and they have a slightly increased speed over their predecessors of 320 km/h.
Thalys PBKA
Unlike Thalys PBA sets, the PBKA (Paris-Brussels-Köln (Cologne)-Amsterdam) sets were built exclusively for the Thalys service. They are technologically similar to TGV Duplex sets, but do not feature bi-level carriages. All of the trains are quadri-currrent, operating under 25kV 50Hz AC (LGVs), 15kV 16 2/3Hz AC (Germany, Switzerland), 3kV DC (Low Countries) and 1,500V DC (French lignes classiques). Their top speed in service is 300 km/h under 25kV 50Hz AC, with two power cars supplying 8,800 kW of power. They have eight carriages and are 200m long, weighing a total of 385t. They have a capacity of 377 seats.
17 trains were ordered: nine by SNCB, six by SNCF and two by NS. Deutsche Bahn contributed to financing two of the SNCB sets.
TGV POS
TGV POS, standing for Paris-Ostfrankreich-Suddeutschland (Paris-Eastern France-Southern Germany) are currently under test for use on the LGV Est, currently under construction.
It will consist of two power cars with eight TGV Réseau type carriages, with a total power output of 9,600 kW and a top speed of 320 km/h. Unlike TGV-A, TGV-R and TGV-D, it has adopted asynchronous motors and in case of failure, isolation of an individual motor in a powered bogie is possible. They will weigh 423t.
Network
France has around 1,200 km of LGV built over the past 20 years, with four new lines either proposed or under construction.
Existing lines
- LGV Sud-Est (Paris Gare de Lyon to Lyon-Perrache), the first LGV (opened 1981)
- LGV Atlantique (Paris Gare Montparnasse to Tours and Le Mans) (opened 1990)
- LGV Nord Europe (Paris Gare du Nord to Lille and Brussels and on towards London, Amsterdam and Cologne) (opened 1993)
- LGV Méditerranée (An extension of LGV Sud-Est: Lyon to Marseille Saint-Charles) (opened 2001)
- LGV Interconnexion (LGV Sud-Est to LGV Nord Europe, east of Paris)
Planned lines
- LGV Est (Paris Gare de l'Est-Strasbourg) (under construction, to open 2007) [1]
- LGV Rhin-Rhône (Strasbourg-Lyon)
- Barcelona-Perpignan-Montpellier, which would connect the TGV to the Spanish AVE network
- Lyon-Chambéry-Turin, which would extend the TGV into Italy
- LGV Sud-Ouest Tours-Bordeaux and LGV Bretagne-Pays de la Loire Le Mans-Rennes, extending the LGV Atlantique
- Bordeaux-Toulouse-Narbonne
- Poitiers-Limoges
Amsterdam and Cologne are already served by Thalys TGV trains running on ordinary track, though these connections are being upgraded to high-speed rail. London is presently served by Eurostar TGV trains running at high speeds via the partially-completed Channel Tunnel Rail Link and then at normal speeds along regular tracks through the London suburbs, although Eurostar will use a fully-segregated line once Section 2 of the link is complete.
TGV outside France
TGV technology has been adopted in a number of other countries:
- AVE, the high-speed network in Spain
- KTX, the high-speed network in South Korea
- Acela Express, a high-speed tilting train built by TGV participant Bombardier for the United States, which uses TGV motor technology (though the rest of the train is unrelated)
Impact
TGV lines have largely replaced air traffic between connected cities. Brussels–Paris in 90 minutes has increased commuting between the two capitals, and likewise the Paris–Marseille line has greatly reduced travel time. Towns such as Tours are becoming a part of "TGV commuter belt".
See also
References
External links
- English version of SNCF official TGV website
- The history of the TGV
- TGV - The French High-speed Train Service at h2g2
- LGV2030: an unofficial website about TGV Network in 2030
