The Hyperloop is technically possible. It will struggle for the same reason Maglev struggled: It won't be cost effective to build or maintain within the safety factors people are comfortable with.
You really have to look at the history of Maglev because the parallels are considerable. Maglev undeniably works, but nobody is building Maglev systems aside from a few pet vanity projects because High Speed Rail is "Good Enough" and cheap!
Hyperloop takes all of the cost issues that Maglev had and makes them worse. Even if the tube didn't have a negative pressure (just a tube with atmospheric pressure) it would be a cost nightmare, but you add in the costs of building something which can withstand negative pressures and the whole thing is just a farce.
Maglev, like Hyperloop, initially wanted to build on raised towers. But it largely wasn't because being able to escape during an emergency is kind of a big deal, same reason why the Euro-Tunnel is 2x larger than it needs to be to support escape tunnels.
A project like Hyperloop won't ever be able to win against real life problems like bombings, earthquakes, fires, extreme weather, and so on. Or at least it won't within the normal realms of cost.
> nobody is building Maglev systems aside from a few pet vanity projects because High Speed Rail is "Good Enough" and cheap!
Japan is building the Chuo Shinkansen, which will be a major intercity Maglev line. It's expected to connect Tokyo and Nagoya in 40mins, down from 100mins on the Tokaido Shinkansen (although a good chunk of that is due to a more direct route through the mountains), and later Osaka.
I could believe it's not necessarily a cost effective investment, but I don't know if I'd call it a vanity project. My impression is that they're trying to duplicate the success of the original Shinkansen, by building something similarly ahead of its time.
Given this is the UAE, I'm not sure they care about the costs. :)
For them, this is just another innovation to put the country on the map of the world as an innovative and futuristic place, and that attracts tourism; which is said to be a large part of the economy here.
In addition to what the other guy said, think about vulnerability to terrorism.
Blow up a support for a segment of tube in the right spot at the right time, and you turn the train into a kinetic kill weapon. (it's traveling 50% faster than a 747!) I'd hate to see that done when it was going through a city.
Blow up a support at any point at the right time, and you've murdered a tube of passengers, plus completely shut down an entire segment of transportation infrastructure for a significant amount of time. Do you know how much it cost the US to shut down all air traffic on 9/11?
Basically, hyperloop is a lot more feasible in a world without homicidal nutjobs - but, alas...
I have a different POV on this given I currently live in Dubai, UAE. They have a 74KM automated rail system (Dubai Metro) and most of it is built on raised towers. This proposed system from what I understand is going to cross mostly empty dessert area.
Secondly, UAE is a pretty safe country in terms of terrorism. At least thats the perception you get if you live here. I haven't heard of one terrorism related activity here. That may be because the media is tightly controlled, but word still gets out if something that major were to happen here. This might just be because they have very tightly controlled borders, and are surrounded by friendly states that also have a relatively good security record (Saudi, Oman).
Just my take on these issues. I don't have any hard data, this is just my perception from having spent 3 years in this country.
