http://themindunleashed.org/2014/08/...-railroad.html

I couldn't image, except wasting money and Open Source kicking butt.

Thanks, Jamison.... hadn't seen this and I'm always up for reading about this amazing man's projects.

It's a grate idea. Can't believe thoughts of it have been around 200 years?

Probably another fantasy born of a trust-fund baby with time on his hands.

As any engineer would instantly know, "first you have to have a sustainable vacuum, and a tube that stretches underground from LA to New York ... right through, by the by, the Rocky Mountains, the Appalachians and so-on."

And that's why people ignore people like that. Except for the good ol' Popular Science magazine, which sold lots of copies of engineering-fantasy (complete with plans for ray-guns in the back pages). Some of which "fantasies," of course, came true. But, not this one.

Not quite. His proposal is for above-ground low-pressure tubes, preferably next to existing highways, which would be a lot more doable.
Now, I'm not saying I'm not sceptical but it's not quite as fruit-loop as it sounds and not much of a stretch from existing maglev systems.

So, tell me, what happens at 14,000 MPH if some part of the pipe bursts ? I won't be finding out, but someone else probably will. It's pure sci-fi, like space elevators and railroads across oceans.

The proposal isn't actually to travel at that speed but a much lower speed like 700MPH to 800MPH which, again, isn't all that much of a leap from modern maglev.
As I see it what he's really proposing, if you forget the sci-fi fun for a moment, is that instead of making these bullet trains force themselves through lots of air at these high velocities we enclose them in tubes and suck a lot of the air out in order to allow them to travel faster.

That's better, but what happens if someone on the train opens/breaks a window ? I suppose if you put oxygen masks like on an airplane, it would be equivalent.

Still, I don't see how you can keep the tubes in a partial vacuum. It will probably leak and you'll have to keep pumps running all the time.

At slower speed and above ground it might be plausible. Underground you would have to build extremely tough tubes, because the vacuum would cause even more pressure from the ground around the tube, the net inward pressure would be increased.

Yes, the cabin would have to be pressurised just like a plane but that's been a solved problem for years. Also, yes, it is proposed that it be above ground on posts much like traditional maglev.
I think the article is doing a good idea a disservice by misrepresenting it as something fantastical and revolutionary when in reality it's just an evolution of existing technology. Still "Musk Proposes Improved High-Speed Maglev Design" doesn't get as many clicks as "Musk Proposes 14,000MPH Super-Train!!!!".

I haven't seen any proposals for railroads across oceans but as for space elevators they are sci-fi because the materials either don't exist at all or can't be yet made on a large enough scale to do any good. The tube train concept afaik only requires conventional materials and techniques. It only requires the will and the funding which, according to his cost analysis is less per mile than the one given the "go light".

Obviously the 14,000 mph title is sci-fi for many reasons (and it is not what Mr Musk proposed) but safety is pretty low on that list. Over 80% of impacts at speeds greater than 40 mph are fatal to those involved. Just how much more dead can one be? The added energy from such speeds poses more danger to the surroundings in the event of catastrophic failure but I suspect, considering the closed environment, that would be of less concern than with current aircraft.

The tube at my bank shoots my money so fast it's not even funny. Tho the cost difference (not so much so) and speeds proposed do seem a little farfetched?

Another thing to note about space elevators are the colossal voltage differences between different layers of the atmosphere. I don't know what effects it will have if it could be built, but there will be effects from the metal structure melting to weather and atmospheric effects.

The money would be better spent to support and improve existing passenger rail.

As an ex-railroader, I have a question: how are you going to switch trains in motion from one vacuum tube to another in real time? (By the way, that's the same reason monorails remain little more than a toy for vacationers.)

Do a search on breakdowns on the (under) channel train - most recently last month.
Would you really want to be in a (elevated) vacuum tube when the inevitable happened ?.

Yep, a fantasy looking for Federal money. A fantasy of traveling Mach 18.25 in a vacuum tube whose vacuum is (somehow, magically ...) sustained over the course of two thousand surface miles ... up and down over mountains and so-forth no problem, straight-line distance measure no doubt.

Now, let's see how we can make Uncle Sugar part with a couple billion trillion (think big™ ...) dollars to pay for this:

• We need it to keep up with the Russians. (Naah, too 1960's.)
• We need it to keep America competitive in physics and science. (Naah, since we "outsource" everything now, we don't need physics or science.)
• We need it to get undocumented workers to our asparagus fields at high speed. (Now, that's got possibilities ...)
• We need it to Keep America Safe From Ter'rists™ !!! ("Dingdingdingdingding! You've got it!!! Let the good times roll!!!")

I wish that I could add a " " after this ...