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Hyperloop One claims that its prototype ultra-fast train has completed a first full systems test in a vacuum, reaching a speed of 70 mph. The sled was able to magnetically levitate on the track for 5.3 seconds and “reached nearly 2Gs of acceleration,” according to the company.
The test was conducted privately but Hyperloop One offered some video that included footage from testing. Based on that footage plus a few seconds of additional b-roll shared with media, a lightweight skeleton sled uses a linear motor to accelerate, levitates briefly, and then comes to a halt as the brakes are applied.
Hyperloop One was created as an answer to a challenge from Tesla and SpaceX CEO Elon Musk, who wrote a white paper envisioning a mode of transportation that would send pods at speeds greater than 700mph using a low-friction environment and levitation using air bearings.
Source: Ars Technica
(Score: 2) by Arik on Friday July 14 2017, @09:49AM (46 children)
This sounds like a great idea until you think about it for 10 seconds. They're proposing to built a tubular vaccum chamber thousands of times larger than any ever made before, for less money than a high speed rail line(!) and then send passengers down it at 600mph. Nothing they've produced so far comes anywhere near that, of course, but let's assume they manage to make that work anyway. One microscopic breach anyway in that tube and the entire thing collapses, and all the passengers inside are dead.
This is actually an incredibly stupid idea and the more closely you look at it the worse it gets. But hey, fools and their money are soon parted when Musky is around.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by RamiK on Friday July 14 2017, @10:26AM (2 children)
Doesn't this full-scale video of the men sitting in the remote control room wearing light reflective vests, baseball caps and helmets at hands' reach while a big metal skateboard is seen screeching through a tunnel for a full 5 seconds fill you with confidence? Can't you see how happy and confident everyone is? Look how many monitors they've got! Look at those smiles! Look at all those beautiful people! How could it possibly go wrong?!
compiling...
(Score: 1) by khallow on Friday July 14 2017, @10:47AM (1 child)
(Score: 0) by Anonymous Coward on Friday July 14 2017, @12:30PM
I can only imagine the original production script called for white lab coats but someone noted that's too cliche* so they ended up with those reflective safety vests and helmets like the Bond villain minions.
* http://tvtropes.org/pmwiki/pmwiki.php/Main/LabcoatOfScienceAndMedicine [tvtropes.org]
(Score: 2) by PiMuNu on Friday July 14 2017, @10:29AM (11 children)
> They're proposing to built a tubular vaccum chamber thousands of times larger than any ever made before, for less money than a high speed rail line(!)
Don't forget the maglev...
> One microscopic breach anyway in that tube and the entire thing collapses
Why?
(Score: 2) by Arik on Friday July 14 2017, @11:27AM (9 children)
But the answer is because objects under vacuum are bearing a constant, heavy load of atmospheric pressure. What happens to things that bear constant loads when their ability to bear that load is suddenly impaired, whether by outside damage or long term strain or corrosion or what have you? They can and do collapse catastrophically. One tiny little flaw starts a chain reaction and in a fraction of a second everything is suddenly different.
Maintaining a vacuum is hard, and it's very stressful on the machinery. The worlds largest vacuum chamber (NASAs SPF) is only 37mx30m surrounded by thick concrete etc., and it is not expected to hold day after day week after week - most of the time it's at normal pressure so that extremely meticulous maintenance can be maintained. They're talking about building a *300 mile long* vacuum chamber out of thin steel tubes and maintaining constant vacuum through summer days and winter nights year round.
With passengers flying down it at 600mph.
He's selling the Brooklyn Bridge, he just updated it.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by PiMuNu on Friday July 14 2017, @11:58AM (8 children)
A vacuum cleaner maintains similar pressure differential (I looked it up, wikipedia said vacuum cleaner is at 0.2 bar, so 0.8 bar pressure differential vs 0.999 bar pressure differential for hyperloop). The difference isnt so huge. Typically, pressure vessels are hard (e.g. diving bottles) because you get ~ few 100 bar. I don't think vacuum vessels are very tricky. I found this
http://engineersedge.com/material_science/pressure_vessel_required_shell_thickness_chart_13162.htm [engineersedge.com]
I had to convert the units; 1 bar is 14.5 psi and 160 inches is 4 metres; so they need 3/16 inches of steel to cope with a few bar overpressure. I assume this chart is for overpressure (i.e. dealing with more pressure inside than outside), I didnt quickly find the equivalent for underpressure but I don't think it will be very much different. The point is it is standard engineering.
==
I thought you might claim that an air leak will cause catastrophic failure because the maglev train has to be able to cope aerodynamically with entering non-zero air pressure. That would be a reasonable statement, but needs detailed study to demonstrate passenger safety.
(Score: 2) by Arik on Friday July 14 2017, @12:20PM (6 children)
Ok so you pay out the nose for numerous maintenance crews and have them crawling the entire length of it day and night. And you don't hesitate to take it offline for maintenance, even though that costs you tons of money and sends unhappy would-be customers to the competition. Can't take chances, so you do the right thing, good for you.
You know what probably happens next? One of the maintenance guys drops a wrench and it hits the tube. Boom. Catastrophic failure.
"I thought you might claim that an air leak will cause catastrophic failure because the maglev train has to be able to cope aerodynamically with entering non-zero air pressure."
That's a perfectly valid point but it is weaker. Clearly this thing isn't going to work right with the vacuum compromised in any way - otherwise we wouldn't be going to all the trouble of making it run in vacuum right? Losing vacuum is going to be very bad. But it seems reasonable to expect they *could* cover that possibility programmatically by bringing everything to a halt in a controlled manner. There doesn't seem to be anything in their current plans about regular escape hatches for frightened passengers to crawl out of in such an event, and if we were going into real depth I would certainly bring this up - but the whole catastrophic failure at 600mph thing is just more important and less debateable.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by PiMuNu on Friday July 14 2017, @01:01PM (5 children)
> As I said, the tube can cope with the pressure normally. The issue is that you have several hundred miles of it exposed to the environment and every inch would have to be *meticulously* maintained.
I just disagree. A long stretch of tunnel will presumably have gate valves installed (standard tech, albeit bigger) so sections can be taken down for maintenance. Maintenance outages are what is done on e.g. UK trains and roads, where long stretches of railway and lanes of motorway are taken down every weekend for maintenance. Random result from google:
https://www.gov.uk/government/news/night-closures-planned-for-m6-cheshire-smart-motorway [www.gov.uk]
I don't see that this scheme is super dangerous/sensitive like you say. Its a couple inches thick steel walled tunnel. A dropped wrench is not going to blow it up.
This is just not high tech. If it splits, it doesn't explode or anything - that happens to gas bottles at hundreds of bar, but not a pressure vessel at 1 bar. It just lets up the pressure in the tunnel. Oh dear, we close off a section of tunnel and get a bus to bring the passengers out, or send in the rescue train, or whatever scheme they invent. Everyone grumbles because they are a couple of hours late to work.
(Score: 2) by Arik on Friday July 14 2017, @01:28PM (4 children)
That's a good idea, but (correct me if I'm wrong) not one that seems to appear in their plans. But I'll give it to you, so you can seal a section and repressurize it and work on it, wonderful!
But you don't want to do that when you have a whole procession of passenger cars hurtling down the tunnel toward that section at 600mph+. Obviously you have to first stop adding passengers, second wait for those already in to complete their journey, then THIRD you can take the section down for maintenance. This process, assuming their own projections, means a minimum of 35 minutes PLUS the actual time required on-site, for each incident.
But more importantly, it means that no matter how badly you may need to shut it down NOW you MUST wait the 35 minutes for it to clear.
You're not just stopping a mag sled that's running in a vacuum at 600mph+ with significant mass on a dime. Plus as I said their plans offer no hint as to any exit capabilities in the transit tube, even were it feasible to stop the sled without killing the passengers.
"https://www.gov.uk/government/news/night-closures-planned-for-m6-cheshire-smart-motorway"
Oh come on! That's a motorway, it's not pressurized, individual cars have their own motors and drivers (and steering) etc. The situations have virtually nothing in common, that's a joke?
If laughter is the best medicine, who are the best doctors?
(Score: 2) by PiMuNu on Friday July 14 2017, @01:56PM
> Oh come on! That's a motorway, it's not pressurized, individual cars have their own motors and drivers (and steering) etc.
> The situations have virtually nothing in common, that's a joke?
My point was for the bureaucracy - shutting down for maintenance is an accepted practice in modern transport infrastructure.
I reckon agree to disagree. I just think you are massively overegging the challenges. Anyway, hope they figure it out...
(Score: 1) by khallow on Saturday July 15 2017, @02:47AM (2 children)
Or you can divert those vehicles to another tunnel. I think the real problem with something like this is what happens when a huge stretch of the track is damaged. I don't buy that a minor leak can cascade to total collapse. But there are several sorts of accidents and sabotage that can take out a long stretch of track, say a raging forest fire, large airplane that crashes along the length of the Hyperloop, or a diligent saboteur with a lot of explosives. Replacing a lot of track lengths at once may be very difficult to do especially, if the manufacture of these components has been scaled down to maintenance level replacement. While most such normal rail is relatively easy to replace in comparison.
(Score: 2) by Arik on Saturday July 15 2017, @05:55AM (1 child)
There are only to be 2 - one running each way. Their plans are quite explicit on that.
I'm not saying this thing can't be built. I'm saying it would either be 1) tremendously and unacceptably prone to cause death if completed as presented and 2) if modified enough to avoid 1 it will no longer be competitive economically. The whole pitch here is the idea that not only can this be done, but it can be done safely and inexpensively, and that is simply bullshit. You can run add backup lanes and figure out SOME way to guide a mag sled hurtling along at 600miles an hour into it safely, you can wrap your steel tubes in concrete and more steel and install sensors and servos and...it's already going to cost orders of magnitude more to build and operate. And it no longer looks good next to the alternatives. And there are still LOTS of devils left to solve... no this is not a technology project. It may be, as another poster suggested, quite a successful scheme to get VC to develop components wanted for an entirely different project instead, but it certainly will never and could never work as advertised.
If laughter is the best medicine, who are the best doctors?
(Score: 1) by khallow on Saturday July 15 2017, @12:32PM
I don't take their plans seriously at this point. A lot of what they would need to know about viable infrastructure, they'll learn later.
You're not presenting a serious argument either. A double shell would work here. The outer shell would shield from most external impacts and provide structural integrity, and the inner shell maintain the vacuum (including a safety margin for dents and such). You don't need massive infrastructure just to maintain a volume of vacuum. We already have companies that make large and often complex steel tubes for the oil industry and such. That infrastructure can be retooled to make Hyperloop sections, should that turn out to be a viable idea.
(Score: 2, Insightful) by Anonymous Coward on Friday July 14 2017, @05:28PM
A vacuum cleaner maintains similar pressure differential
One pinprick through a vacuum cleaner hose starts a chain reaction and in a fraction of a second, BOOM! 🎆 Up you go in a cloud of mushrooms! ☁️🍄 Your city, too. It's Hiroshima all over again. MAN WAS NOT MEANT TO KNOW THE POWER OF THE VACUUM!!!
(Score: 0) by Anonymous Coward on Friday July 14 2017, @11:10PM
https://www.youtube.com/watch?v=T9bpUfWy8Wg [youtube.com]
Something about like this.
and this
https://www.youtube.com/watch?v=AL4k9BGv_Gg [youtube.com]
and this
https://www.youtube.com/watch?v=G-3WiTMgSQ8 [youtube.com]
That is about what it will be like. Remember with these vids were not 'total near vacuum' like they are talking about in the hyperloop.
I have 0 doubt they will make a very long track. Manage to maglev a train in it in a vacuum. But they have a serious engineering problem they are not even talking about. It is a science experiment I learned in 5th grade with some water and steam and a sealed tin can.
The atmosphere weighs quite a bit. Also nature abhors a vacuum.
If they just get collapse it should not be a total loss. But if they get a rupture (likely) it would probably be a near total loss for most of the system.
(Score: 1) by khallow on Friday July 14 2017, @10:38AM (16 children)
You'll need a massive structural failure at minimum. Microscopic breaches will just leak air in.
Let us keep in mind that one can build high speed rail lines for much less than current too.
(Score: 2) by Arik on Friday July 14 2017, @11:10AM (15 children)
Yeah no. /me facepalms.
The issue is that once you draw that vacuum those metal tubes have to bear atmospheric pressure alone and continuously. Fine, they can do that, but the situation is on a knife's edge, it's not safe, because not even a breach, just a tiny *dent* or a microscopic stress factor or any of dozens of tiny things can catastrophically weaken the tube, triggering a sudden collapse. It's not always a full collapse, no, there are several modes of failure and it's hard to predict which will happen. The most catastrophic outcome would be a full vacuum collapse* but even if only a small portion buckles what happens when a passenger car going 600mph just barely clips that buckled portion going by, hmmm?
There are good reasons why the worlds largest vacuum chamber is only a little over a thousand square meters.
*It's not a webpage but it does host a 4 minute show and tell video to help with this concept: https://www.youtube.com/watch?v=0N17tEW_WEU
If laughter is the best medicine, who are the best doctors?
(Score: 1) by khallow on Friday July 14 2017, @12:32PM (4 children)
Sorry, air pressure isn't infinite force here. A tiny dent, etc would at first just create a tiny leak. Just implement designs that inhibit crack propagation and don't send your vehicles through a zone with a rupture.
Why would that happen? Buckling leads to leaks (and you can independently detect buckling with external sensors) which leads to near instant leak detection.
And one of those good reasons is that they didn't have a good reason for anything bigger. High speed transport creates such a reason.
(Score: 2) by Arik on Friday July 14 2017, @12:53PM (3 children)
No, it's not infinite force and it doesn't need to be.
"A tiny dent, etc would at first just create a tiny leak."
No, in fact, that's very often not what happens. Instead the tiny dent compromises the structure enough that it's no longer able to resist the atmospheric pressure and it collapses suddenly.
"Why would that happen? Buckling leads to leaks (and you can independently detect buckling with external sensors) which leads to near instant leak detection."
A tube holding a temperature differential works very much like an arch holding up a building works. The curved structure can withstand incredible compression, but if you first set the compression, then cause some tiny bit of damage to the structure, it can collapse almost instantaneously as well.
So by the time you detect the leak it may well be too late to do anything about it.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by Nuke on Friday July 14 2017, @07:40PM
While I think the Hyperloop will be a white elephant, your argument is just not true. You can design a vacuum vessel to withstand dents, it is just a matter of how strong you make it and the nature of the material. Assuming the Hyperloop designers have some sanity, they will not create a design that is on the brink of implosion.
The comparison with an arch is misleading as people wil think of a masonry one, and masonry is brittle and also cannot withstand much tension. A Hyperloop tube (or steel arch) would be made of structural steel which is mallable and work-hardening. I have done structural analysis of major structures (at nuclear power stations) and the consideration, and analysis of departures from perfect geometry is routine. Even masonry arches don't collapse just like that - the medieval arch bridges in Europe are doing fine, despite plenty of your "tiny bits of damage", and worse.
If you make a big enough dent in a Hyperloop tube then eventually it might implode, but to make such a dent we would be talking about bombs or aircraft crashes, which no transport mode can withstand anyway. We do consider aircraft and bombs hitting power stations though.
(Score: 1) by khallow on Friday July 14 2017, @10:50PM (1 child)
As Nuke noted, it depends what you make the structure out of and what the load is. There are arches which can withstand a lot of damage. If this shell is built so that it barely withstands atmospheric pressure under the best of circumstances, then someone is doing it wrong. There should be ample margin of safety precisely because we don't want this collapsing like an aluminum can.
(Score: 1) by baldrick on Saturday July 15 2017, @03:46AM
each car should be checking the structure - a la intelligent pig
... I obey the Laws of Physics
(Score: 2) by PiMuNu on Friday July 14 2017, @01:08PM (2 children)
The diameter of the tunnel is the crucial factor, not the volume. Maybe that is why you are confused?
(Score: 1) by Arik on Friday July 14 2017, @01:31PM (1 child)
Also did you watch the video? That tanker-car was about the right diameter, a little small actually.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by PiMuNu on Friday July 14 2017, @04:36PM
I've seen the video before. So use thicker steel? Reinforcement girders? Don't make the vacuum vessel cylindrical? I mean this is not rocket science!
(Score: 2, Insightful) by FatPhil on Friday July 14 2017, @01:50PM (5 children)
Mythbusters tanker collapse was -23"Hg, with only 22% of the prior air in it.
Musk is aiming for a 99.9% vacuum with only .1% of the prior air in it.
So it's clear that Musk is aiming for something that is 300 times harder a vacuum than that tank, and 220 times harder than Mythbusters'.
Let's say he gets to 99% rather than 99.9% - that looks quite close, doesn't it? But no, it's a factor of 10 out, 1% versus .1% remaining, which means the drag will be 10 times higher than intended, thus the power will need to be 10 times higher too. So it will be very easy for his "energy efficient" means of transport to suddenly become not even pipe dream, but pipe nightmare.
And let's not even think about heading in the direction of considering what Tim McVeigh could do with it.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 1) by Arik on Friday July 14 2017, @02:04PM (3 children)
If laughter is the best medicine, who are the best doctors?
(Score: 2) by FatPhil on Friday July 14 2017, @02:47PM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Friday July 14 2017, @03:12PM (1 child)
The thing that a lot of people miss is that you don't even need a complete collapse of a section to be fatal to anybody in the tube at the time. All it needs is to dent enough that the capsule catches on the dent in order to be a catastrophic failure that would destroy a portion of the tube, the capsule and anybody in it.
(Score: 1) by khallow on Saturday July 15 2017, @02:07AM
I guess that depends on how close the capsule is to the shell of the tube. But if it's not close, then you'll need a huge dent. Events that make huge dents are easy to detect. Huge dents are easy to detect as well.
(Score: 2) by andersjm on Saturday July 15 2017, @10:06AM
The pressure on a 70% vacuum container is 0.7 bar. The pressure on a 99.9999% vacuum is 1 bar. That's not really a lot! The risk of structural failure for a roundish thing due to being subjected to 1 bar outside pressure is basically zero.
There's an engineering challenge in sealing to create and maintain a high vacuum, but there is no "Tim McVeigh" scenario.
(Score: 2) by wonkey_monkey on Friday July 14 2017, @03:40PM
It's significantly larger than that, and of the many good reasons, cost and necessity are among them. No-one's going to build a much bigger vacuum chamber without a pressing need.
None of your posts seem to have any numbers to back them up. You just keep saying "It'll collapse! It'll collapse!"
systemd is Roko's Basilisk
(Score: 2) by FatPhil on Friday July 14 2017, @11:10AM (9 children)
Even if it is reasonably energy efficient, this jumps out as making the thing rather impractical:
"The pods would each carry 28 passengers and depart every two minutes from either location (or every 30 seconds at peak times). So each pod would have about 23 miles between one another while traversing the tube. The transport capacity would therefore be about 840 passengers per hour."
That's a pathetic number - that's a single local-transit train (and for example the London underground has more than *500* of those rattling around it sumultaniously every day (and yup, that does work out to nearly half a million people on the move simultaniously)).
It seems like the most convincing answer to "why are you doing this?" is "because we think we can".
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 2) by rondon on Friday July 14 2017, @11:34AM (3 children)
Do all the flights from San Fran to LA equal more than 840 passengers per hour? Because if not, it isn't an unreasonable amount of passengers.
This wasn't designed as "local transit." I feel like this is a straw man, but perhaps I am missing something.
That being said, I'm not sure the idea is feasible for its many, many other limitations.
(Score: 2) by Arik on Friday July 14 2017, @11:54AM
There was a Brookings report from 2009 that put it at "more than 6 million people" per year, but that sounds like individual people not trips. Some people make a lot of trips. And how much has that changed since 2009? If you assume one trip per person per year and no change you'd 684 - less than what the 'hyperloop' is supposed to be able to handle, but not by a lot. The real number seems very likely to be significantly higher than that.
If laughter is the best medicine, who are the best doctors?
(Score: 2) by FatPhil on Friday July 14 2017, @12:31PM
Being local, it has the highest stop-go overheads, therefore the lowest average speed. Standing space on the tube gives them a capacity boost per unit length, but of course they are shorter, so only carry 50% more than a TGV, say, whilst travelling at a fifth of the speed (a completely bumhole-sourced number). Nett, that makes HSTs 3 times more competitive assuming equal intervals, and the TVG has 20 in flight at any one time on its busiest lines, which means in total it's 2x as competitive as the tube.
Looks like my presumptions were fair.
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 3, Interesting) by Aiwendil on Friday July 14 2017, @01:17PM
TGV (the french highspeed trains) take between 245 and 750 seated passengers per set. Those are not local transit either. In general such a train can do just with less than five minutes per stop. So, with TGV you wouldn't even blink at 2500 to 9000 passengers per hour.
The Alstom Coradia (common train here in sweden [X40], albeit a double-decker) is a train aimed at the up to 200kph service, and it takes between 153 and 252 seated passengers per set. So even there we are talking about 1500-3000passengers per hour. In china they even have a few �trains [Regina] in the up to 200kph class with a seated passenger capacity in excess of 1000 per set (so noone would even flinch at 12_000 seated passengers per hour - once they get used to the sense of scale in china that is) [in sweden normally in the 145 to 267 range of seated (shorter sets)]
Let's just say that to get down to 840 passengers per train for a proper distance train you need to hit either low traffic (15min intervals) or use short old-interior trains (less than about 120 passengers).
Oh, and for the trains above, that is per track that has a platform. Since doubletracks are common on new lines (needed for high speed anyway) double the capacities per platform. When not having to stop the trains can be packed even tighter (some 30s between them if you go automatic).
The thing is 840passengers per hour is very low capacity, it is basically the suburbs to a smallish [1-2million] capital capacity levels.
(Score: 2) by GreatAuntAnesthesia on Friday July 14 2017, @02:57PM
No, the answer is "because why should I pay my own money to research, develop and test the technologies needed for a vacuum tube / railgun equatorial launch system capable of blasting my food, air, water and Tesla into orbit and thence my Martian retirement home when I can get credible investors and governments to fund it for me?"
(Score: 2) by Nuke on Friday July 14 2017, @07:49PM (1 child)
Indeed it is, and you did not need to go into the separation distance. 28*60/2 = 840
What people don't get is that Hyperloop would be the Concorde of the railway world - just for a few millionaires and birthday treats.
(Score: 0) by Anonymous Coward on Friday July 14 2017, @08:45PM
It's the Concorde, the Hindenburg, the Titanic and the Quintinshill signal box all in one, according to some of the posters here.
(Score: 1) by khallow on Friday July 14 2017, @11:05PM (1 child)
At peak times, that would be 3,360 passengers per hour (quadruple the rate you used for your calculation).
(Score: 2) by FatPhil on Monday July 17 2017, @01:37PM
Great minds discuss ideas; average minds discuss events; small minds discuss people; the smallest discuss themselves
(Score: 0) by Anonymous Coward on Friday July 14 2017, @04:49PM
Hahahah the joke is on you. You think Musk ever was going to use this on Earth!? This is a ploy to get people interested in R&D his train for Mars, where you don't need vacuum, you just have to keep the dust out of it, and the lesser gravity makes the levitation a lot easier.
(Score: 4, Insightful) by Sulla on Friday July 14 2017, @04:58PM
"You would make a ship sail against the wind and currents by lighting a bonfire under her decks? I pray you excuse me. I have no time to listen to such nonsense" - Napoleon
Ceterum censeo Sinae esse delendam
(Score: 1, Insightful) by Anonymous Coward on Friday July 14 2017, @09:01PM
If catastrophic failure could occur in the event of a microscopic breach at 1 bar, then how do submarines regularly survive leaks at any depth greater than 33 ft? (every 33ft of depth adds approx. 1 bar)
(Score: 0) by Anonymous Coward on Friday July 14 2017, @09:31PM
Someone stop the madness before it's too late!!!