Achieving World-Record Speeds through the Power of Magnets
The L0 model superconducting linear train (C)CENTRAL JAPAN RAILWAY COMPANY
The interior fittings of the L0 model superconducting linear train. (C)CENTRAL JAPAN RAILWAY COMPANY
Since the development of the Shinkansen bullet train in the 1960s, Japan has led the world in the field of advanced rail technology. The Linear High-Speed Train, which uses electromagnetic fields for extra-fast speeds, is Japan's latest breakthrough. After fifty years of development, a test version of the new technology recently recorded a speed of 581 kilometers per hour—a world record for a manned vehicle.
The train is driven by a new kind of motor called a superconducting linear motor. This works on the principle of magnets. As you probably know, the north and south poles of a magnet attract, whereas two poles that are the same (north and north, or south and south) repel each other. The new technology uses this principle to push the train forward, using the attracting and repelling forces created by coils in the tracks and magnets inside the train.
An illustration showing the train from above.
Fixed on the ground along with the propulsion coils that move the train forward are also other coils that lift and guide the train. When the magnets in the train run past the levitation coils, an electric current passes through these levitation guide coils, creating an electromagnetic field. The coils in the tracks and the train both produce a magnetic field, and the train is held in position by the pushing and pulling forces between these two magnetic fields. These same forces also help to keep the train positioned properly in the middle of the tracks. In the past, trains used friction generated between the wheels and the rails to drive them forward, but at high speeds this friction is lost, causing the wheels to idle and resulting in a loss of speed. With the new system, the train is suspended above the rails, making it possible to travel at higher speeds than ever regardless of friction.
A front-on view of the train.