Physically impossible? Maybe, but the vacuum tube part was actually insane. It would have been insanely difficult to maintain a useful enough vacuum over huge

Physically impossible? Maybe, but the vacuum tube part was actually insane. It would have been insanely difficult to maintain a useful enough vacuum over huge distances that the hyperloop was supposed to run. A single failure in such a system could have catastrophic consequences across a huge range. edit: beaten by @tsimionescu by a minute.