TGV

The Train à Grande Vitesse (TGV) was inaugurated in 1981 (27 September) with a service between Paris and Lyon in the traditional orange livery (since changed to the blue and silver livery common to all series except the Thalys). Initially developed for SNCF by the British company GEC and the French company Alstom (now all built by Alstom), it is, without doubt, one of France's greatest engineering feats and its success and popularity with the travelling public has led to an immense expansion of the network throughout France and into neighbouring countries – Switzerland, Belgium, Germany and Holland – as well as, with the TGV derivative Eurostar (see separate display), England. The Spanish AVE and the South Korean KTX trains are also based on the TGV design.

The original plan was to have the trains propelled by gas turbines, driving electric motors, it being thought at the time that high-speed pick-up from overhead wires would not be feasible. However, during design and testing it became apparent that electric traction using overhead catenary (25,000 volts) was preferable. The trains are maintained in units of ten or twelve carriages (including two power cars) that are, apart from the power cars, articulated (two carriages share a common bogie), giving a smoother ride at high speed. Each line has a slightly different specification for its trains including the new Duplex series (double decker) for use on high-density routes.

The burgundy-liveried Thalys series are used on routes from Paris to Belgium, Holland and Germany, some of them also duplex style as are many of the blue liveried TGV sets shown below. The TGV holds the world speed record for a train – 574.8 km/hr (in excess of 357 mph) – though this was a test-run and not a passenger service. The normal operating speed of TGVs in service is around 320 km/hr (just under 200 mph). The TGV has largely replaced air travel on routes from Paris in the 300 mile radius and its speed has brought many towns at some distance from Paris within the "commuter belt".

The TGV runs on dedicated high-speed tracks to avoid encountering slower trains, but into many of the main stations it shares tracks with 'ordinary' trains. To ensure passenger comfort the radius on high speed lines is a minimum of 4 kms, though on newer lines it is 7 kms. A TGV produces about 12,500 hp.

As the speeds are so high, normal colour-light signals cannot be used, so signalling is in-cab, with electrical pulses sent through the rails to advise the driver on the current speed restriction, the target speed for that and the following sections and several other important aspects to ensure he operates the train within specific speed restrictions. There is also a system to ensure he remains fully alert to the changing conditions and he is required to press certain buttons at random to confirm that he is wide awake and in control ! Each section is marked off by both in-cab indications and also by a large blue and yellow "flag" panel beside the tracks.

A new development of the TGV will be the AVG (automotrice à grande vitesse), being extensively tested now in the Czech Republic. The major difference between the TGV and AGV is that the latter will have traction motors beneath each car rather than having the power units at each end as the TGV now has. This leads to better weight distribution and more efficient running, as well as freeing up two extra carriages for additional seating. Pretty well all other high speed trains already use this arrangement (except Eurostar and the HST 125 in the UK).

The TGV map of towns and cities (and countries) served is ever-growing, adding better services for passengers, taking traffic off the roads and railways on short-haul services, and adding to a better infrastructure for those countries in which it operates.