A short history of transportation
Railways, with steel wheels running on steel rails, changed the industrial world in the early 1800’s. The world then had fast, efficient transport replacing the existing slow horse-drawn steel-rimmed wooden wheels on rough roads.
Then in 1890, Joseph Dunlop invented the pneumatic tire, which gave a soft ride and good grip. This made the motor car possible with higher speeds and comfort on the rough roads of the day. Despite their early unreliability, the versatility of the pneumatic tire has enabled rapid growth of road transport compared to rail. Today, 96% of land transport uses pneumatic tires.
But there has always been a fascination with ‘modern’ alternatives to the humble wheel. The British invented the Hovercraft in the 1950’s, and for the next 20 years there were substantial R&D projects in UK and France to try to develop high-speed transport using air cushion suspension.
Maglev is the most fascinating technology, the allure of non-contact, frictionless transport has attracted great enthusiasm and significant research over the last 70 years. But after $billions of R&D, and only one high-speed maglev in service, maglev has failed to deliver practical transport. Research has declined over the last 10-15 years, but now there is renewed interest in maglev for Hyperloop projects.
Maglev using copper coils along the whole route would be the ideal levitation system, but extreme expense may make it impossible. See maglev coils here.
Maglev has always been promoted as frictionless, high efficiency transport. But in fact the energy consumption is much higher than high-speed-rail, due to inefficiency of its non-contact traction system. See maglev energy here.
Hyperloop Alpha originally proposed air ski bearings for levitation. But there is insufficient airflow in the near-vacuum to make it possible. See air skis here.