Aérotrain

The Aérotrain was a Hovertrain 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.

Test Tracks

The track for most Aérotrains are ferroconcrete monorail in an inverted '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 Aérotrains 01 and 02, re-using an abandoned railway formation. The track was 6.7 km long. The track is 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 Aérotrain prototype S44 in Gometz-le-Châtel, built 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.

• In 1969, a third, 18 km test track was built to test Aérotrain prototype I80. This test track was in Loiret, France, north from Orléans, stretching between Saran and Ruan, a location that would enable it to be used in a future Paris-Orléans line. The track was elevated 5 m above the ground, was supported by pillars and allowed speeds of 400 km/h. A platform stood at each end of the line to reverse the train, while a hangar on the central platform at Chevilly housed the test vehicle. This line, while abandoned, became a famous landmark subject to cosmetic disputes after the end of the Aérotrain programme, and exists today, visible to the east of RN20 and the Paris-Orléans railway line.

• Until 1974, a fourth, 1.5 miles (2.4 km) test track was built at the High Speed Ground Test Center near Pueblo, USA. This test track was built for the UTACV prototype. Due to its length, it was suited only for a top speed of 145 mph (233 km/h).^[1]

Aérotrain prototypes

Five prototypes were built:

• Aérotrain 01 was a 1/2 scale (10.11 m, 2.6 t) prototype. It was originally propelled by a three-bladed reversible-pitch propeller powered by a 260 horsepower (190 kW) aircraft engine, which was later replaced by a Turboméca Marboré jet engine. The air cushion is maintained by two 50 horsepower (37 kW) compressors. 01 had place for four passengers and two crew.

• Aérotrain 02 (shown in picture) was another sub-scale prototype, seating two crew. It was powered by a Pratt & Whitney JT12 turbojet.

• Aérotrain S44 was a full-size passenger-carrying car intended for suburban commuter service at speeds of 200 km/h (in particular links between city centres and airports). It was equipped with a Linear Induction Motor (linear motor) propulsion system supplied by Merlin-Gérin.

• Aérotrain I80 was a full-size passenger-carrying car for intercity service. It was 25.6 m long, 3.2 m wide, 3.3 m high, had a mass of 11.25 t empty, and had 80 passenger seats. In its original configuration (as I80-250 for 250 km/h), it was propelled by twin Turboméca Turmo III E3 turboshaft (1,610 horsepower (1,200 kW) each) powering a ducted propeller, 2.3 m in diameter, with seven blades of variable pitch. A Turboméca Turmastazou 14 turboshaft engine powered the air compressors (six horizontal for the support and six vertical for guidance). Braking was typically provided by reverse thrust of the propeller, and in emergencies by a friction brake on the central rail. External noise was 90-95 dBA at 65 yards (59 m).^[2] I80-250 was later rebuilt for 350 km/h and re-designated as the I-80 HV (Haute Vitesse = high speed). The main change was the new propulsion system, a JT8 D11 turbofan from Pratt & Whitney mounted on top. I-80 HV established the world speed record for overland air cushion vehicles on 5 March 1974 with a mean speed of 417.6 km/h (259.5 mph) and a peak speed of 430.4 km/h (267.4 mph).

• UTACV was a prototype built by Rohr Industries for the US DOT's TACV program, built under the Bertin Aérotrain licence in the USA.

The Rohr Aerotrain

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.^[3]

The Rohr prototype, officially called the Urban Tracked Air Cushion Vehicle (UTACV)^[4] and colloquially the Rohr Aerotrain, was propelled by linear motor and was designed to carry 60 passengers at 150 mph (240 km/h).^[1] 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 Aerotrain was never commercialized. The Rohr prototype aérotrain remained on the premises of the Pueblo Weisbrod Aircraft Museum until July 2009. The prototype is now located at the Pueblo Railway museum.^[5][6] The museum plans to open an aerotrain exhibition within the test vehicle in the next few months.^[7]

Timeline

• 1963: Jean Bertin presents a 1/12 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 the first prototype, Aérotrain 01.
• 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: equipped with a jet engine, Aérotrain 01 reaches a speed of 345 km/h.^[2]
• 1967: construction of Aérotrain 02.^[2]
• May 1967: tests start with Aérotrain 02 on the Gometz-le-Châtel trial track, 300 km/h is attained.
• 22 January 1969: with the addition of a rocket, Aérotrain 02 reaches the record speed of 422 km/h.^[2]
• 1969: construction of an experimental 18 km track between Ruan, to the north of Artenay, and Saran (Orléans) in the Loiret.
• 7 July 1969: the Aérotrain I80 prototype for 250 km/h is presented to the public.
• September 1969: tests start with Aérotrain I80 on the Orléans test track. 250 km/h is attained on the 13th.
• 1969: construction of the Aérotrain S44. In tests from December 1969 to January 1972, it achieved 170 km/h on a 3 km long test track.
• 7 March 1970: release of a postage stamp honoring the Aérotrain.
• 1970: Rohr Industries starts the construction of the UTACV prototype in the USA.
• October 1973: Reconstruction of the Aérotrain I80 for 350 km/h as the I80 HV.
• 1974: The government abandons the project for the construction of an Aérotrain line between the Orly and Roissy airports for another between La Défense and Cergy in the Paris metro area.
• 5 March 1974: The Aérotrain I80 HV breaks the land speed record for rail vehicles for air cushioned vehicle at 430.4 km/h.
• 21 June 1974: The contract about a commercial line between La Défense and Cergy is signed.
• 17 July 1974: The government abandons the La Défense-Cergy project.
• September 1975: Announcement of a TGV line to be constructed between Paris and Lyon.
• 1974: start of testing with the Rohr Industries UTACV prototype at the High Speed Ground Test Center near Pueblo, USA.
• October 1975: the Rohr Industries UTACV prototype is mothballed after funding for the programme runs out.
• 21 December 1975: Jean Bertin dies.
• 17 July 1991: A fire destroys the Aérotrain S44 in its hangar at Gometz.
• 22 March 1992: A fire destroys the Aérotrain I80 HV 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 commemorated 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.

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 fuel used by the Aérotrain I80 and TGV alike became costly for a time. The TGV switched to using cheap electricity from France's abundant nuclear power. The aérotrain could have done the same with further development by using a linear motor, an electric motor driven fan or wheel propulsion system. It is uncertain whether it would have been 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

• 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.^[2]

Aérotrain shares these advantages and disadvantages with the magnetic levitation train and thus may have been a competitor where maglev has been used.

Other experimental hovercraft trains

• 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.
• In Britain a similar technology was developed under the name of Tracked Hovercraft.

See also

• Hovertrain
• Tracked Hovercraft
• Ground effect train
• Otis Hovair
• N500 Naviplane
• Transrapid 03
• Schienenzeppelin, a 1930s German train using a propeller but on a conventional track
• Minneapolis-St. Paul Airport Trams
• Skymetro
• Huntsville Hospital Tram System
• Duke University Medical Center Patient Rapid Transit
• Narita Airport Terminal 2 Shuttle System,These cars do not have wheels; instead, they float on a 0.2-millimetre layer of pressured air.The system is made by Otis Elevator.

References

External links

• Aérotrain photo library and forum
• Aérotrain and Naviplanes
• SHONNER Studios: The Rohr Aerotrain Tracked Air-Cushion Vehicle
• Aero-Train ~ a high-speed traffic system of zero emission~
• Sonicbomb videoclip