That vacuum chamber has two sets of fifty foot tall doors. The hyperloop is an inch-thick welded steel tube. Pinholes are trivially detected by ultrasonic tes

That vacuum chamber has two sets of fifty foot tall doors. The hyperloop is an inch-thick welded steel tube. Pinholes are trivially detected by ultrasonic testers. There are no leaks. Even hydrogen and helium would take centuries to diffuse inside. The only problems are sealing the ends, which are a couple meters wide. The hyperloop as written was very challenging, but the engineering aspects are not. The practical building (grinding the inside, transporting the tubes, etc.) are significant. The financing is insane. The theory is not even particularly hard, much less at the level of a space elevator.