At that time, about 1960, a radical new concept was thought up; combining very high speeds and steep grades would allow a railway to follow the contours of existing terrain, like a gentle roller coaster.
Over the next several years, this very general idea gave rise to a variety of high speed transportation concepts, which tended to move away from conventional "wheel on rail" vehicles.
Indeed, the French government at the time favoured more "modern" air-cushioned or maglev trains, such as Bertin's Aérotrain; Steel wheel on rail was considered a dead-end technology.
Simultaneously, SNCF (the French national railways) was trying to raise the speeds of conventional trains into the range 180 to 200 km/h (110 to 125 mph) for non-electrified sections, by using gas turbines for propulsion.
Energy was reasonably cheap in those years, and gas turbines (originally designed for helicopters) were a compact and efficient way to fulfil requirements for more power.
The desire for higher speeds and the successful development of the turbotrain program are two ideas that came together in the late 1960s, further spurred on by the 1964 start of the Japanese Shinkansen high-speed train.
The TGV 001 turbotrain was a test train for a vast research program encompassing traction, vehicle dynamics, braking, aerodynamics, signalling, and other technologies that needed to be developed to allow higher speeds.
This afforded a greater stability (by coupling the dynamics of carbodies) and made space for a pneumatic secondary suspension placed level with the centre of gravity, thus reducing roll in curves.
The TGV 001 test campaign was an invaluable part of project C03, proving new concepts in a realistic environment and giving extensive engineering data on high-speed operation.
Using this vehicle, the new Y226 long-wheelbase power truck (precursor of the Y230 of the production TGV) was developed and tested, with its body-mounted traction motors and tripod cardan transmission.
Body mounting of the traction motors was a major innovation; it allowed a considerable (3300 kg) reduction in the mass of the power truck, giving it a very high critical speed and exceptional tracking stability.
The interior spaces had to be welcoming and comfortable, restful, quiet, easy to clean and fix, and smoothly integrated together to create a uniform atmosphere.
This was quite in contrast with the previous record of 331 kilometres per hour (206 mph), set on 28 March 1955 by a pair of French electric locomotives, the CC 7107 and the BB 9004.
On 27 September 1981, to great fanfare, the first TGV with paying passengers left Paris, after the inauguration by then French president François Mitterrand five days earlier.