You're right, I'm using vacuum as a layman's term, and shorthand for "hard vacuum" as mentioned in the paper. [0] The paper refers to the Hyperloop system as a

You're right, I'm using vacuum as a layman's term, and shorthand for "hard vacuum" as mentioned in the paper. [0] The paper refers to the Hyperloop system as a "a low pressure (vs. almost no pressure) system". [0]: http://www.spacex.com/sites/spacex/files/hyperloop_alpha.pdf http://www.spacex.com/sites/spacex/files/hyperloop_alpha.pdf (p3)