Gyro monorail

A gyro monorail, gyroscopic monorail, gyro-stabilized monorail, or Brennan monorail is a single-rail land vehicle that uses the gyroscopic action of one or more spinning wheels to overcome the inherent instability of balancing atop a single rail. For a similar steerable vehicle, see Gyrocar. The monorail is associated with the names Louis Brennan, August Scherl and Pyotr Shilovsky, who each built full-scale working prototypes during the early part of the twentieth century. A version was developed by Ernest F. Swinney, Harry Ferreira and Louis E. Swinney in the US in 1962. The gyro monorail was never developed beyond the prototype stage. The principal advantage of the monorail cited by Shilovsky is the suppression of hunting oscillation, a speed limitation encountered by conventional railways at the time. Also, sharper turns are possible compared to the multi-kilometre radius of turn typical of modern high-speed trains such as the TGV, because the vehicle will bank automatically on bends, like an aircraft, so that no lateral centrifugal acceleration is experienced on board. A major drawback is that many cars – including passenger and freight cars, not just the locomotive – would require a powered gyroscope to stay upright. Unlike other means of maintaining balance, such as lateral shifting of the centre of gravity or the use of reaction wheels, the gyroscopic balancing system is statically stable, so that the control system serves only to impart dynamic stability. The active part of the balancing system is therefore more accurately described as a roll damper.

History

Brennan's monorail

Louis Brennan developed a 22-tonne (22-long-ton; 24-short-ton) (unladen weight) prototype vehicle. Brennan filed his first monorail patent in 1903. His first demonstration model was just a 30.0-by-11.8-inch (762 by 300 mm) box containing the balancing system. However, this was sufficient for the Army Council to recommend a sum of £10,000 for the development of a full-size vehicle. This was vetoed by their Financial Department. However, the Army found £2,000 from various sources to fund Brennan's work. Within this budget Brennan produced a larger model, 6.0 by 1.5 feet (1.83 by 0.46 m), kept in balance by two 5.0-inch (127 mm) diameter gyroscope rotors. This model is still in existence in the London Science Museum. The track for the vehicle was laid in the grounds of Brennan's house in Gillingham, Kent. It consisted of ordinary gas piping laid on wooden sleepers, with a 50-foot (15 m) wire rope bridge, sharp corners and slopes up to one in five. Brennan demonstrated his model in a lecture to the Royal Society in 1907 when it was shown running back and forth "on a taught and slender wire" "under the perfect control of the inventor". Brennan's reduced scale railway largely vindicated the War Department's initial enthusiasm. However, the election in 1906 of a Liberal government, with policies of financial retrenchment, effectively stopped the funding from the Army. However, the India Office voted an advance of £6,000 (equivalent to £624,053 in 2025) in 1907 to develop the monorail for the North West Frontier region, and a further £5,000 (equivalent to £520,044 in 2025) was advanced by the Durbar of Kashmir in 1908. This money was almost spent by January 1909, when the India Office advanced a further £2,000 (equivalent to £205,828 in 2025). On 15 October 1909, the railcar ran under its own power for the first time, carrying 32 people around the factory. The vehicle had a 20-horsepower (15 kW) petrol engine with a speed of 22 miles per hour (35 km/h). The transmission was electric, with the petrol engine driving a generator, and electric motors located on both bogies. This generator also supplied power to the gyro motors and the air compressor. The balancing system used a pneumatic servo, rather than the friction wheels used in the earlier model. The gyros were located in the cab, although Brennan planned to re-site them under the floor of the vehicle before displaying the vehicle in public, but the unveiling of Scherl's machine forced him to bring forward the first public demonstration to 10 November 1909. There was insufficient time to re-position the gyros before the monorail's public debut. In December 1909, Brennan demonstrated the railcar to the Royal Society. It carried 40 people at a speed of 40 km/h (25 mph) on a single-rail circular track that was 200 m (660 ft) in circumference. The length, height, and width of the vehicle was 12.2 m × 4.0 m × 3.0 m (40 ft × 13 ft × 10 ft). The public debut for Brennan's monorail was the Japan-British Exhibition at the White City, London in 1910. The monorail car carried 50 passengers at a time around a circular track at 20 miles per hour (32 km/h). Passengers included Winston Churchill, who showed considerable enthusiasm. Interest was such that children's clockwork monorail toys, single-wheeled and gyro-stabilised, were produced in England and Germany. Although a viable means of transport, the monorail failed to attract further investment. Of the two vehicles built, one was sold as scrap, and the other was used as a park shelter until 1930.

Scherl's car Just as Brennan completed testing his vehicle, August Scherl, a German publisher and philanthropist, announced a public demonstration of the gyro monorail which he had developed in Germany. The demonstration was to take place on Wednesday 10 November 1909 at the Berlin Zoological Gardens.

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