Aérotrain

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For the article about the passenger train consist built by General Motors Electro-Motive Division, see Aerotrain (GM).
Aérotrain prototype #02

The Aérotrain was a hovercraft train developed in France from 1965 to 1977. The lead engineer was Jean Bertin.

The goal of the Aérotrain was similar to that of the magnetic levitation train: to suspend the train above the tracks so the only resistance is that of air resistance. Consequently the Aérotrain could travel at very high speeds with reasonable energy consumption and noise levels, but without the technical complexity and expensive tracks of magnetic levitation.

Five prototypes were built: 01, 02 (shown in picture), S44, I-80 and I-80 HV. I-80 was a full-size 80-passenger car running on 18 km of track. It established the world speed record for overland air cushion vehicles on March 5 1974 with a mean speed of 417.6 km/h and a peak speed of 430 km/h.

This project was abandoned in 1977 due to lack of funding, the death of Jean Bertin and the adoption of TGV by the French government as its high-speed ground transport solution.

Time Line

  • 1963: Jean Bertin presents a 1/12th scale model, 1.4 meters in length, to the public authorities and to SNCF.
  • 15 April, 1965: creation of the Société d’étude de l’Aérotrain (Company for the study of the Aérotrain).
  • 16 December, 1965: completion of the construction of Aérotrain 01, a 1/2 scale prototype, which can carry four passengers and two crew. It is propelled by a propellor powered by a 260 horsepower aircraft engine. The air cushion is maintained by two 50 horsepower compressors. It is 10.1 meters long with a weight of 2.6 metric tons.
  • 21 February, 1966: official inauguration in Essonne of the 6.7 km trial track for Aérotrain 01 between Gometz-le-Châtel and Limours (on the abandoned easement of the Paris-Chartres via Gallardon line). That day, in front of the press, Aérotrain 01 reaches 100 km/h. Days later it reaches 200 km/h.
  • 23 December, 1966: with the addition of a rocket, giving a combined power of 1700 horsepower, the Aérotrain 01 reaches a speed of 303 km/h.
  • 1 November, 1967: the Aérotrain 01 is equipped with a turboprop engine, reaching a speed of 345 km/h.[1]
  • 1967: construction of Aérotrain 02. It is powered by a JT12 turboprop from Pratt & Whitney.
  • 22 January, 1969: Aérotrain 02 reaches the record speed of 422 km/h on the Gometz-le-Châtel trial track.[1]
  • 1969: construction of an experiemtal 18 km track between Ruan, in the North of Artenay and Saran in the Loiret. The track is elevated 5 meters above the ground and is supported by pillers. It is built on an alignment that would allow it to be used in a future Paris-Orléans line. The alignment allows speeds of 400 km/h. It is equipped with a platform at each end of the line allowing the turning of the aérotrain and a central platform at Chevilly allowing the aérotrain to be housed in a hangar. This line, while abandoned, still exists today.
  • 1969: construction the Aérotrain I80. This vehicle is 25.6 metres long, 3.2 metres wide, 3.3 metres high, weighs 11.25 metric tons empty and has 80 passenger seats. It is propelled by twin Turboméca Turmo III E3 turbines powering a ducted propellor, 2.3 meters in diameter, with seven blades. A Turmastazou 14 turbo engine powers the air compressors (six horizontal for the support and six vertical for guidance). Breaking is typically provided by reverse thrust of the propellor, and in emergencies by a friction brake on the central rail. External noise is 90-95 dBA at 65 yards.[1]
  • 1969: construction of the Aérotrain S44, a version designed for suburban transport (links between city centres and airports) with electric propulsion. It is equipped with a Merlin-Gérin linear motor and designed for a speed of 200 km/h.
  • 7 March, 1970: release of a postage stamp honouring the aérotrain.
  • 1973: Realisation of a high speed version of the Aérotrain I80, the I80HV (Haute Vitesse). This version is powered by a JT8 D11 turbofan from Pratt & Whitney.
  • 1974: The government abandons the project for the construction of an aérotrain line between the Orly and Roissy airports.
  • 5 March, 1974: The Aérotrain I80 breaks the land speed record for railed vehicles for air cushioned vehicle at 417.6 km/h.
  • September, 1975: Announcement of a TGV line to be constructed between Paris and Lyon.
  • 21 December, 1975: Jean Bertin dies.
  • 1977: The project is abandoned.
  • July, 2004: The memory of the trials on the Gometz line is memorialized by the dedication of a roundabout in Gometz and a sculpture by Georges Saulterre representing the Aérotrain.

Comparison with TGV

The aérotrain was abandoned by the French government in favour of TGV. A short comparison is given below.

Advantages of TGV

  • Unlike aérotrain, TGV could use existing rail lines in metropolitan areas. Aérotrain would have required new lines, easements and stations in metropolitan areas.
  • As developed, the aérotrain had much lower capacity.
  • After the first oil shock, the chemical propulsion used by the Aérotrain I80 would be too costly, thus requiring propulsion by electric linear motor. This may have been much more expensive than the wheel based propulsion used by TGV.
  • The rail world was totally unfamiliar with the technology used by the aérotrain.

Advantages of Aérotrain

  • Demonstrated possibility of significantly greater speeds compared to TGV.
  • Less pressure on track, with possible lower construction and maintenance costs.
  • Less friction, with possible lower energy requirements.
  • Less noise, because it had no wheels and transmitted less vibration to the track.[1]

It should be noted that aérotrain shares these advantages and disadvantages with the magnetic levitation train and thus may have been a competitor where maglev has been used.

The American Aérotrain

In 1970, Rohr Industries decided to develop an aérotrain 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 aérotrain was propelled by linear motor and was designed to carry 60 passengers at 150 mph (240 km/h). It had a length of 94 ft (28 m) and an empty weight of 46,000 pounds (20.8 metric tons).

A test track was built in Pueblo, Colorado, where the prototype reached speeds of 145 mph (constrained by the length of track). Funding from UMTA ceased and the Rohr Industries Aérotrain was never commercialized.

In Britain a similar technology was developed under the name of tracked hovercraft or hovertrain, mainly by Eric Laithwaite However, this development effort did not get as far as the aérotrain technology. There was an attempt to build a test track but this failed due to civil engineering problems [1].

References

  1. ↑ 1.0 1.1 1.2 1.3 "Société de L'Aerotrain, France". Jane's Surface Skimmers Hovercraft and Hydrofoils: pp. 144-148. Ed. Roy McLeavy. Jane's Yearbooks, London. Cite error: Invalid <ref> tag; name "Jane" defined multiple times with different content Cite error: Invalid <ref> tag; name "Jane" defined multiple times with different content Cite error: Invalid <ref> tag; name "Jane" defined multiple times with different content

External links

Pictures

Videos

paris/orléans en 25 minutes ! le projet de jean bertin, un train sur coussins d'air...450km/h en 1970!!!

450km/h sur coussins d'air en 1968 !!

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