Maglev technology has been under development all around the world for decades. So why is it confined to east Asia today?

Maglev brings to mind The Future. Arguably, it has been doing so for more than a century – the concept dates back to the early 1900s, when German engineer Alfred Zehden was awarded a patent for a system that would propel a train using magnetism.

In basic terms, maglev is a form of high-speed transportation in which a train is held above its tracks with magnetic levitation (from which the word maglev is derived). There is variation between designs: they can be monorail or dual rail; use conventional or supercooled, superconducting electromagnets; or even be slotted inside gigantic vacuum tubes to minimise drag. What these models all have in common, and what distinguishes them from conventional high-speed rail, is levitation and lack of an engine: strong magnetic fields hold the train several centimetres above the track, keep it horizontally stable and propel it forward...