What is Hyperloop? How does it work? What speeds are proposed?
Hyperloop is a proposed mode of passenger and freight transportation that propels a pod-like vehicle through a near-vacuum tube at airline speeds. The pods accelerate to cruising speed gradually using a linear electric motor and glide above their track using passive magnetic levitation or air bearings. The tubes can 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. Tesla and SpaceX's Elon Musk has started the building revolution for this new train system dubbed Hyperloop. It will mean getting from LA to San Francisco in under 30 minutes.
It's based on the very high speed transit (VHST) system proposed in 1972 which combines a magnetic levitation train and a low pressure transit tube. It evolves some of the original ideas of VHST, but still uses tunnels and pods or capsules to move from place to place. One of the biggest problems with anything moving, is friction, both against surfaces and the environment the pod is moving through. Hyperloop proposes to move away from traditional wheels by using air bearings for pods instead. This will have the pod floating on air. It's similar to maglev in which the electromagnetic levitation of the train means there is no friction like a traditional train that runs on tracks. This is how current maglev trains can achieve super speeds, like the 500km/h maglev train in Japan. The Hyperloop will be built in tunnels that have had some of the air sucked out to lower the pressure. So, like high altitude flying, there's less resistance against the pod moving through the tunnel, meaning it can be much more energy efficient, something that's highly desirable in any transit system.
Hyperloop is being proposed as an alternative to short distance air travel, where the system will be much faster than existing rail networks and much cleaner that flight. Speeds of over 700mph are suggested for journeys, but there are practical implications that have to be considered on a short stop-start journey, such as the acceleration and deceleration sensation that passengers would go through.