Maglev

Maglev (derived from magnetic levitation) is a system of train transportation that is levitated along a guideway through the use of magnetic forces. By levitating, maglev trains remove the rail-to-wheel contact present in conventional railways, eliminating rolling resistance.

Compared to conventional railways, maglev trains can have several advantages, including higher top speeds, superior acceleration and deceleration, lower maintenance costs, improved gradient handling, and lower noise at equivalent speeds. However, maglev systems are more expensive to build, cannot make use of existing infrastructure, and have higher energy usage at high speeds.

Maglev trains have set several speed records. The train speed record of 603 km/h (375 mph) was set by the experimental Japanese L0 Series maglev in 2015. From 2002 until 2021, the record for the highest operational speed of a passenger train of 431 kilometres per hour (268 mph) was held by the Shanghai maglev train, which uses German Transrapid technology. The service connects Shanghai Pudong International Airport and the outskirts of central Pudong, Shanghai. At its historical top speed, it covered the distance of 30.5 kilometres (19 mi) in just over 8 minutes.

Different maglev systems achieve levitation in different ways, which broadly fall into two categories: electromagnetic suspension (EMS) and electrodynamic suspension (EDS). Propulsion is typically provided by a linear motor. The power needed for levitation is typically not a large percentage of the overall energy consumption of a high-speed maglev system. Instead, overcoming drag takes the most energy. Vactrain technology has been proposed as a means to overcome this limitation.

Despite over a century of research and development, there are only six operational maglev trains today — three in China, two in South Korea, and one in Japan.