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24 July 2014

Crackers: High Speed trains

 - Thursday, 19 April 2007, 00:00

When English inventor Richard Trevithick introduced the steam locomotive on 21 February 1804 in Wales, it achieved a speed of

8 km/h. In 1815, Englishman George Stephenson built the world’s first workable steam locomotive, commissioned by the Killingworth colliery. In 1825, he introduced the first passenger train, which steamed along at 25 km/h. Today, trains can fly down the tracks at 500 km/h. And fly they do, not touching the tracks.

Need for rail speed

The need for rail speed escalated when Japan introduced the shinkansen Bullet Train on 1 October 1964 to mark Asia’s first Olympic Games, held in Tokyo. The Bullet Train proved that there is not only fascination, but also a market for fast trains.

In the early 1970s, the French built the TGV (Train à Grande Vitesse). The TGV is the French version of high speed trains. There are many others: more than 350, in fact. The German ICE3, built by Siemens, reaches 330 km/h. The Eurostar comfortably hurls 700 passengers along at 300 km/h, with its two motors pushing out 12,200 kW. Siemens and French Alstrom teamed up for the Spanish Talgo, which will shrink distances at 350 km/h. In Australia, the Speedrail TGV ran the Sydney-Canberra line at up to 360 km/h in 2004. In the US, the Acela flies down the tracks at 320 km/h. Even China is planning a new high speed rail to quickly cover the 1,280km between Beijing and Shanghai. High speed trains also run in Britain, Italy, Belgium, the Netherlands, Switzerland, Taiwan and South Korea. But perhaps Japan is best known for its superfast trains, holding the speed at 552 km/h.

The technology

To achieve amazing speeds, the magnificent powertrains called for new developments in track design. TGV tracks, welded rails on hybrid steel and concrete ties, lay on a thick bed of ballast. The combination of curve radii and super-elevation makes high speed possible: a 5km radius would be considered tight. Instead of each car with its own wheels, they are semi-permanently attached on a two-axle truck between them.

The Maglev is a system in which the train runs levitated from the tracks by using electromagnetic forces between superconducting magnets on board the vehicle and coils on the ground. When the magnets pass at high speed, an electric current is induced within the coils, which then act as electromagnets temporarily. As a result, there are forces which push the superconducting magnet upwards and ones which pull them upwards simultaneously, thereby levitating the Maglev. The repulsive force and the attractive force induced between the magnets propel the Maglev forward at great speed.

Fabulous flying

The Maglev actually does not touch the tracks when travelling. Its superconductors let the trains float above the rails. The Siemens-Alstrom train levitate 1cm above the track. Japan’s shinkansen runs 10cm above the tracks. The shinkansen uses wheels to reach

100 km/h before it levitates. The European model uses regular magnets, but enables immediate flight.

Maglev research started in 1962, and by 1970 studies of electrodynamic levitation systems using superconducting magnets took shape. The first test run took place in 1979. In December 1986, a three-car train registered 352.4 km/h. In December 1997, a manned MLX01 attained 531 km/h and unmanned, attained

550 km/h. The following year, a test of two trains passing each other at a relative speed of 966 km/h was run successfully. In March 1999, an unmanned five-car MLX01 reached 548 km/h. In April, the manned five-car MLX01 set a fabulously fast world speed record at 552 km/h.

How does it stop?

TGVs have dynamic brakes, with brake shoes for emergency stops. Trailers are equipped with four disks per axle, and backup brake shoes. Magnetic induction track brakes are planned for the next models. Maglevs are slowed down in the same way it is propelled, by superconducting magnets.

High speed lines are completely fenced off, and the tracks maintained in top condition. Although there have been derailments, in the almost two decades of daily operation, there has been no casualties.

At high speed, it is impossible to read lineside signals. All signalling information is transmitted to the train through the rails directly to onboard monitors in the cab. Most of the high speed train functions are controlled digitally, true to being the vehicle of the digital age.

The high speed Shinkansen E2 runs from Nagano to Tokyo

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