Most people aren't aware of the issues facing hyperloop, so allow me to explain why many engineers think it will never happen.

The reason why Hyperloop would be able to travel as fast as they say is because the tube itself would be turned into a giant vacuum, reducing the resistance on the train. In fact Doctor Phil Mason once said that Hyperloop, “might be better described as all the problems of space travel while traveling in a gun barrel at the speed of sound". In fact, there are a ton of problems with even building it. First of all, the air pump required to pump the air out of the Hyperloop would have to pump out 2 million cubic meters of air. To put that in perspective, the world's most powerful air pump only does about 1.5% of that.

That isn't taking into account the logistics of building something that would be dangerous not just to passengers but because he wants to build it along the freeways, dangerous to everyone for miles if there is even a small breach. Imagine an explosion where the bomb was stretched from Seattle to Portland, and even a small malfunction created an unstoppable chain-reaction that set it off, spreading at the speed of sound.

There are a slew of other issues, such as expansion of heat and cold, but you get the idea. The Hyperloop is a (excuse the pun) pipe dream.