Don't see why this isn't completely feasible except return on investment for building it.

Acceleration isn't an issue for the 620mph design


Obviously design would use much more controlled acceleration with the magnetic rail system

And vacuum sealing the tube? Not a big feat either. Commercial steam turbine exhausts operate at almost absolute zero pressure continuously. Designed for 1.5"hg that's like 3/4 Psia. Sealing a turbine with multiple shafts and bearing housings in atmosphere is more difficult that a sealed tube as described.

This post was edited by FullArcFG on Jul 25 2018 04:48pm

i don't see how technology could be liberal lol

Technology is not, the disbursement of the budget as well as many other considerations is subject to liberal or conservative policies.

This post was edited by SBD on Jul 25 2018 04:56pm

Do not mix vacuum tube & magnetic levitation...

vacuum tube lenght ?

We could do it, but it would be so expensive to run and maintain, as well as dangerous that it would never turn a profit.

This

Quite frankly, most of Elon Musk's urban transportation solutions are stupid. It is not that we don't have the technology to make them work, it is that they are highly impractical, and not at all cost effective.

The only way the hyperloop would be practical is if they could reach and maintain speeds that conventional bullet trains can not. It would not be a practical solution for short range travel for a lot of reasons. If it only carried one person at a time, they have to queue up for it, and if it carries a lot of people at a time, they would need to have a boarding process. Either way they are adding a lot of time spent waiting, so the actual time saved vs conventional means of travel over short distances would be marginal at a huge initial investment cost. So it would have to be for long distances. Basically it would need to be a mag rail in a vacuum tunnel on a very straight track. The original idea of a steel tube built above ground is not feasible because steal expands and contracts with temperature changes, making it impractical to build a tube miles long exposed to sunlight. There are also a lot of security risks involved.

The only way to make it practical would be to make it an underground tunnel which is innately climate controlled, and long enough that the boarding/exiting of it would take a relatively small amount of time compared to that saved by using it to travel. In which case it would be competing with conventional passenger jets So it would need a noticeable shorter boarding process, and/or travel faster than an average 600mph long enough to make it time effective. Of course, because of security concerns there would be a long boarding time, compounded by how big their individual cars/capsules/trains are. If they make them too small they would have to have them set at certain intervals for safety and then there would be queue times, and still wait times for safety checks. Ideally there would a size that in which the boarding process would be relatively fast and smooth, and which all safety checks can be done while the boarding process takes place. Lets say 50 people in 15 minutes, combined with a wait time and security checks, ideally only taking another 15 minutes. So, lets say from entering the station to leaving on the mag bus, it is a half hour process. Then, lets say the tube goes from DC to NY, 200 miles, with an average speed of 2000mph. So 6 minutes. Then you have to claim your luggage and leave the station, say 14 minutes for the purposes of rounding. That means from the time they enter the station to the time they leave the destination they have spent 50 minutes. However only 6 minutes traveling. A conventional bullet train could do that same trip in 50 minutes, but would have a longer boarding and luggage recover time period. Lets say total time is 125 minutes. 2.5x longer. But what is the cost of building a bullet train compared to building a vaccuum tunnel? Also how much is actually being saved in operating costs or is it costing more?

You see, the longer the distance the more worthwhile it becomes, but for short distances, forget about it, it just is not cost effective at all.

Long distance becomes exponentially more impractical as it becomes a thousand mile long vacuum tube, one leak for any reason shuts the whole thing down immediately and strands passengers.

So there's basically no benefit for short travel and insanely expensive for long travel.

This post was edited by Thor123422 on Jul 29 2018 02:34pm

Thunderfoot has a nice video where he goes through the cost and failure rate for joints to make up for the thermal shifts of, say, going through a desert. It's not a good result for the hyperloop.