TGV High-Speed Rail Network, France

From the first service with fare-paying passengers in September 1981, the French train à grande vitesse (TGV) has in the widest sense set the pace in European high-speed (initially above 200km/h) rail operations.

Not only has the TGV developed with successive fleet orders, the dedicated high-speed network on which they are primarily designed to run, the lignes à grande vitesse (LGV), continues to expand within France and across international borders.

THE PROJECT

The TGV/LGV system evolved from several projects aimed at cutting rail journey times, with hover and magnetic levitation systems, as well as gas turbine propulsion, being discarded along the way.

Assuming the performance available from high-power electrically powered trainsets and not having to account for mixed use, the new twin-track lines could be driven across country, following the landscape with a severity of gradients that previous trains could not handle.

As the aim was to link the largest centres only, intermediate stations, deviations for smaller communities and related track work could be kept to a minimum.

Although environmental consciousness when the first TGVs entered services was not as prevalent as it has since become, even with the power consumption associated with high-speed operation, in relative terms the LGV network is perceived as environmentally sound compared to short/medium-haul air travel or mass use of private cars.

With the cutting of centre-to-centre journey times and a sufficiently attractive pricing policy, wherever the network has expanded, so domestic air traffic has fallen or air routes have ceased completely.

INFRASTRUCTURE

Unlike the Japanese Shinkansen counterpart that largely evolved due to the limitations of narrow gauge lines and thus became an entirely separate network, the LGV was created and continues to be developed within the context of the wider SNCF operation. Standard LGV electrification is 25kV ac, although to allow working onto the other established SNCF system, 1,500V dc, all TGV sets are at least two-system.

Although access for other types is being built into later routes, most LGV are for use by trains of the TGV 'family' only. However, as high-speed trains make use of existing lines, notably to gain access to cities and established stations, many classic routes were substantially reworked. To prolong the life of track formations, strict 17t axle weight limits are imposed on tracks over which TGV run.

While many communities lobbied to be included in the LGV network, mindful of the noise and visual intrusion of high-speed rail operations, SNCF adopted a range of measures aimed at reducing noise disturbance in adjoining new lines.

In order of opening, principal domestic high-speed lines as at 2008 are:

• LGV Sud-Est (Paris-Lyon) – 1981
• LGV Atlantique (Paris-Le Mans and Tours) – 1990
• LGV Rhône-Alpes (Lyon-Valence) – 1992
• LGV Nord (Paris-Lille/Channel Tunnel) – 1993
• LGV Méditerranée (Valence-Marseille) – 2001
• LGV Est (Paris-Baudrecourt) – 2007

To link LGV Sud-Est and LGV Nord, the Interconnexion (Jonction) Est, effectively an eastern bypass of Paris and link to Charles de Gaulle airport and Disneyland Paris, opened in 1994. It has since been connected to LGV Est. A tribute to the infrastructure as well to the capability of the rolling stock, LGV Est was the setting for the world rail speed record for a wheel-driven train of 574.8kph (356mph) in April 2007.

The outstanding safety record of the network has been greatly influenced by the use of the same vehicle type, the absence of at-grade junctions and level crossings, also through lines being fully fenced and sophisticated sensors fitted to detect obstacles getting onto the permanent way.

Although LGV have been highly successful and profitable, a few stations have not shared that popularity, notably Haute Picardie on TGV Nord and the elaborate Gare de Saint-Exupéry (at Lyon airport, originally Satolas).

ROLLING STOCK

Although the initial TGV Sud-Est batch was built for 270km/h (168mph), the majority of TGV operate at a maximum service speed of 300km/h (186mph) or 320km/h (199mph). Newer lines such as LGV Est are built for speeds up to 350km/h. The most significant change over the original format was the TGV Duplex (double deck) variant, built in several batches since 1995 and still in production.

A response to constantly rising demand on the first and busiest LGV, Paris-Lyon, the Duplex sets powered variously by Réseau or differently styled Duplex power cars can carry 545 passengers. Such is demand that the format has spread to other LGV and on LGV Sud-Est, pairs of Duplex are now deployed to get more capacity out of the route.

In June 2007 Alstom won a €2.1bn contract to supply SNCF with 80 more Duplex sets for delivery from 2009 to operate services extending from LGV Est. As speeds render lineside signals ineffective, TGV sets are equipped with in-cab signalling.

A notable development for the French network from 2007 was the introduction of trains from outside the Alstom-built TGV family in the form of specially modified DB ICE3 sets for working services over TGV Est from Paris into Germany.

Although as yet not ordered by SNCF, the next generation of high-speed trains from builder Alstom – formerly Alsthom and GEC-Alsthom – is the AVG (Automotrice à Grande Vitesse). Featuring distributed power rather than separate power cars and with service speeds of 360km, the AVG seems likely to be the future motive power format for the LGV network.

SIGNALLING / COMMUNICATIONS

The nerve centre of TGV operation is is in northern France, situated near the maintenance depot close to Lille Flandres station. Such is the power generated by a TGV that each has to be fitted with an interference current monitoring unit to ensure electrical interference does not exceed safe levels.

Trains are fitted with automatic train protection systems which automatically apply the brakes if a signal is not responded to or passed at danger. TVM430 is a cab-based signalling system which monitors train progress and informs the driver of the maximum speed possible at any given time to maintain headways between trains.

THE FUTURE

More LGV are under construction and others are in varying stages of planning by infrastructure organisation Réseau Ferré de France (RFF). After some uncertainty about the cost-benefit aspect of completing LGV Est, the success of the first phase and the stimulus of creating a trans-Europe high-speed line indicate that the 106km section from Baudrecourt to Vendenheim near Strasbourg will be ready by 2015.

Other RFF projects include LGV Bretagne-Pays de la Loire to reach Rennes and Nantes; LGV Sud Europe Atlantique to reach Bordeaux (with a longer-term extension to the Spanish border); LGV Bordeaux-Toulouse (with a view to link the Atlantic with Mediterranean sections); LGV Provence-Alpes-Côte D'azur (Marseille-Nice: route to be determined).

The mixed-use Languedoc-Roussillon project which is under construction will join the French and Spanish high-speed systems, made possible by the latter using 1,435mm rather than their domestic standard.

The eastern branch of the three-section 425km Rhine-Rhône project (the first long-distance LGV not to be part of the radial pattern from Paris) is under construction and services may begin in 2011. Also in south eastern France is a high-speed portion of the new Turin-Lyon line project.