Hyperloop technology functions somewhat like the pneumatic tubes that bank tellers have used to send checks and cash to customers waiting in the drive-through. Hyperloop passengers will sit in a pod that races through a vacuum tube.

Maintaining a vacuum in the tube is the toughest challenge, according to Satbir Singh, a Carnegie Mellon professor who advises students working on a hyperloop project. If air leaks in during travel, or when people board the hyperloop, the pods won’t be able to travel at top speed.