Hyperloop "is a proposed mode of passenger and freight transportation that would propel a pod-like vehicle through a reduced-pressure tube that would exceed airliner speed. The alpha version of the proposal, published on the SpaceX website, describes design claims of the system, as well as its function.
The pods would accelerate to cruising speed gradually using a linear electric motor and glide above their track using passive magnetic levitation
or air bearings. The tubes could also go above ground on columns or underground, eliminating the dangers of grade crossings.
It is hoped that the system will be highly energy-efficient, quiet and autonomous."
The concept, created by Elon Musk in 2012, incorporates reduced-pressure tubes in which pressurized capsules ride on an air cushion driven by linear induction motors and air compressors...."