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. 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.

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[edit] Test Tracks

The track for most Aérotrains are ferroconcrete monorail in an upside-down T shape. To date, all tracks were built and used for experimental purposes. The first test track was built in February 1966 in Gometz-le-Châtel, Essonne, France, for aerotrains 01 and 02, re-using an abandoned railway path. The track was 6.7 km long. The track is still visible today, partially demolished for urban expansion, with most of the remaining track in ruins. A section was kept and restored as a memorial at a roundabout in Gometz. A second track made of aluminum and asphalt was built in 1969 for aerotrain prototype S44 in Gometz-le-Châtel, built just meters away and parallel to the first track. The aluminium guide rail was disposed of after the tests, the rest of the asphalt track was kept intact and converted into a pedestrian path in 2008 and 2009. A 18 km elevated track was built in 1969 in Loiret, France, north from Orléans, stretching between Saran and Ruan, with the main facility platform located in Chevilly. The Orléans test track was built to test Aérotrain prototypes I80-250 and I80-HV. The Orléans test track became a famous landmark subject to cosmetic disputes after the end of the Aérotrain programme.

[edit] Aérotrain prototypes

Six prototypes were built: 01, 02 (shown in picture), S44, I-80, I-80 HV and the Rohr Industries prototype. 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 (259.5 mph) and a peak speed of 430.4 km/h (267.45 mph). The Rohr Industries prototype was build under the Bertin Aérotrain licence in the USA. Aérotrain prototypes were equipped and tested with variants in the propulsion system: aircraft propeller for aérotrain prototype 01, custom blade pitch propeller for aérotrain prototype I80-250, gas turbine for aérotrains prototypes 02 and I80-HV, electric Linear Induction Motor (linear motor) for aérotrains prototypes S44 and Rohr.

[edit] Timeline

  • 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 propeller powered by a 260 horsepower (190 kW) aircraft engine. The air cushion is maintained by two 50 horsepower (37 kW) compressors. It is 10.1 meters long with a weight of 2.6 metric tons.
  • 21 February 1966: official inauguration in Seine-et-Oise (but now 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 1,700 horsepower (1,300 kW), 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 experimental 18 km track between Ruan, to the north of Artenay, and Saran (Orléans) in the Loiret. Such a location would enable it to be used in a future Paris-Orléans line. The track is elevated 5 meters above the ground, is supported by pillars and allows speeds of 400 km/h. A platform stands at each end of the line to reverse the Aérotrain, while a hangar on the central platform at Chevilly houses the test vehicles. This line, while abandoned, still exists today, and is clearly visible to the east of RN20 and the Paris-Orléans railway line.
  • 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 propeller, 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). Braking is typically provided by reverse thrust of the propeller, and in emergencies by a friction brake on the central rail. External noise is 90-95 dBA at 65 yards (59 m).[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 honoring 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 rail vehicles for air cushioned vehicle at 430.4 km/h.
  • 17 July, 1974: The project is abandoned.
  • September, 1975: Announcement of a TGV line to be constructed between Paris and Lyon.
  • 21 December 1975: Jean Bertin dies.
  • 22 March 1992: A fire destroys the Aérotrain I80 and the hangar at Chevilly. After clean-up operations, only the platform is left.
  • 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.
  • February 2007: A 120-meter-long section of track is destroyed north of the Chevilly platform during the A19 highway construction.

[edit] Comparison with TGV

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

[edit] 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.

[edit] Advantages of Aérotrain

  • 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.

[edit] 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.

Grumman also developed an air-cushion transportation prototype (also known as tracked air cushion vehicle or TACV), tested within the same facility in Pueblo, which also stopped when UMTA funding ceased in the 1970s.

[edit] The British Aérotrain

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].

[edit] See also

[edit] References

  1. ^ a b c d Roy McLeavy, ed. "Société de L'Aerotrain, France". Jane's Surface Skimmers Hovercraft and Hydrofoils. Jane's Yearbooks, London. pp. 144–148. 
  • "Coming: Streamliners Without Wheels." by John Volpe. Popular Science, December 1969. p. 51. Article on tracked air cushion vehicle (a.k.a. aerotrains) research in the U.S.

[edit] External links

Coordinates: 48°01′42″N 1°53′04″E / 48.02833°N 1.88433°E / 48.02833; 1.88433

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