Aérotrain


The Aérotrain was an experimental Tracked Air Cushion Vehicle
, or hovertrain, developed in France from 1965 to 1977 under the engineering leadership of Jean Bertin – and intended to bring the French rail network to the cutting edge of land-based public transportation.
Though similar to a maglev design, which levitates a train car over a complex electromagnetic track to eliminate all resistance other than aerodynamic drag, the Aérotrain – also a "train without wheels" – rode on an air cushion over a simple reinforced concrete track or guideway and could travel at the speed of a maglev train, without the further technical complexity and expense of its track. In many respects, the entire concept resembled a product of the aircraft rather than rail industry.

History

In 1969, an U.S. company, Rohr Industries, Inc., licensed the Aérotrain technology to build the hovertrains in the United States. That same year the Aérotrain established the world record for a TACV, the pilots saying that with a longer track even higher speeds could have been reached without major difficulties. The final prototype, the Aérotrain I80, set a world speed record in 1974 for overland air cushion vehicles, reaching a speed of and a peak speed of. The prototypes, which ultimately used twin turbine engines through a ducted propeller with seven blades, demonstrated they could accelerate and decelerate quickly, which offered a huge advantage of enabling effective service between tightly spaced stops.
US Secretary of Transportation John Volpe, the mayor of Los Angeles and representatives and transportation specialists from over 18 countries came to France and participated in test rides, studied the system and reported on the Aérotrain. Bertin felt the technology was sufficiently realized for full implementation, and the French government signed a contract to implement full-scale service on the outskirts of Paris, between Cergy and La Défense. The Aérotrain nonetheless ran into increasing internal conflicts with its client SNCF, which had no research and development department of its own and strongly favored improving the existing rail system.
Aérotrain faced numerous design challenges. The system would require new elevated guideways for every implementation – further pitting Aérotrain against efforts to improve existing "wheeled" rail system. Bertin's Versailles-based companies, Bertin and Co. and Aeroglide Systems, Inc., worked to resolve issues with sudden changes in air pressure, as when the train would pass another train or enter a tunnel. Prototypes used gas turbines with giant propellers, which created tremendous noise both inside and outside the train car itself – and thus required reduced speeds in urban areas. SNCF felt they already had trains that could run at those reduced speeds. Proponents pointed out electric linear induction motors could make the TACV silent. Eventually SNCF simply opposed the project, citing a broad litany of concerns.
In 1974, after his election as President of France, Valéry Giscard d’Estaing formally annulled the contract for the Aérotrain Cergy-La Défense line and SNCF formally shifted support to the Train à Grande Vitesse as its high-speed ground-transportation solution. Notably, D'Estaing's wife was the granddaughter of Eugène Schneider, founder of what became an international syndicate, Schneider Group. Noted Belgian journalist Karel Vereycken pointed out: "the Schneider dynasty have been and are still a pillar of the history of the French railroad and steel industry. Hence, the innovation of the Aérotrain would not, in the short run, have made them more wealthy and one can easily imagine that a train without wheels does not get much enthusiastic approval of the feudal wheel producers." Rohr abandoned the technology in 1975.

Test tracks

Most of the track for the Aérotrain was constructed of ferroconcrete to provide an inverted "T" shape for the monorail, with the tracks ultimately used only for experimental purposes.
Five prototypes were built:
In 1970, Rohr Industries decided to develop a tracked air-cushion vehicle as part of a project by the Urban Mass Transit Administration to sponsor development of new mass-transit technology to meet future transit requirements.
The Rohr prototype, officially called the Urban Tracked Air Cushion Vehicle and colloquially the Rohr Aerotrain, was propelled by linear motor and was designed to carry 60 passengers at 240 km/h. It had a length of 28 m and an empty weight of 20.8 tonnes.
A test track was built in Pueblo, Colorado, where the prototype reached speeds of, constrained by the length of track. Funding from UMTA ceased and the Rohr Industries Aérotrain was never commercialized. The Rohr prototype Aérotrain remained on the premises of the Pueblo Weisbrod Aircraft Museum from approximately 1978 until July 2009, whereupon it was moved to the Pueblo Railway museum. The museum plans to open an Aérotrain exhibit within the test vehicle.

Timeline

Jean Bertin, suffering with cancer and overworked after a decade of effort, died in December 1975. The I-80 Aérotrain made its last trip on December 27, 1977. On July 17, 1991, the S-44 Aérotrain prototype was destroyed by fire in its storage facility at Gometz-la-Ville and in 1992 the I-80 prototype was destroyed in Chevilly by arson. Of the four prototypes that had been built, the last two remain stored in France.
Jean Bertin's company, now, remains in business, focusing on the aerospace, defense, and transportation sectors. Outside Orléans, the remains of the abandoned and partially-demolished elevated concrete test track still stand to this day, easily visible from the parallel SNCF Paris-Orléans railway.