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Hyperloop Testing Starts Next Year
neanderslob writes: In 2013, Elon Musk told us about a theoretical transportation system he'd been thinking about for a while. It was called "hyperloop," and it was a tube-based system capable of sending people and things at speeds of up to 800mph. Now, a company called Hyperloop Transportation Technologies plans to start construction on an actual hyperloop next year. The idea is to build it to serve Quay Valley (a proposed 75,000-resident solar power city in Kings County, California). The project will be paid for with $100 million the company expects to raise through a direct public offering in the third quarter of this year. The track itself will be a 5-mile loop and won't reach anywhere close to the 800mph Musk proposed in his white paper — but it's a start.
Next up, Musk-branded suicide booths.
100 mile long is fine as long as it fires me off the end, pointing to the sky at 800mph and wearing a wing suit
Breathless headline: We're testing a Hyperloop next year! It's almost ready to go NOW!!!
Summary: Um, we're still producing CGI and real-estate brochures. You just have to trust us!
So both the city and the hyperloop dont exist yet.
thinking now of the chicken and the egg problem.
also thinking now of how long the germans have been testing their maglev trains and they still arent deployed for the public anywhere
US to Australia could be a direct Hyperloop?
Meaning the Boeing 747 became extremely popular while the Concord wound up eventually going to the dustbin of history because per passenger-mile, the Boeing 747 was cheaper than the Concord, despite taking much longer to move passengers from New York to London.
And that's the problem I see with the Hyperloop: sure, it may be technically possible to send passengers in a train in a tube with a vacuum at 800 miles per hour from Los Angeles to New York, but at the end of the day, its the cost per passenger mile that matters. And a large airplane traveling along at 500 miles per hour, which doesn't require 3,000 miles of dedicated hardware to travel through, is going to be far cheaper than buying a 3,000 mile strip of land and building a tube. across it.
And we call it a crematoria.
And a large airplane traveling along at 500 miles per hour, which doesn't require 3,000 miles of dedicated hardware to travel through, is going to be far cheaper than buying a 3,000 mile strip of land and building a tube. across it.
Depends on how many total passengers over the lifetime.
Perhaps we won't see a 3000 km long hyperloop, but there's plenty of places where a shorter one would fit. I put it in the same league as Maglev, which also requires a specialised track.
Tourist.
It's not new and it's not his idea.
https://www.youtube.com/watch?...
I had a toy that back in the late 70's that was essentially the same thing.
I am Bennett Haselton! I am Bennett Haselton!
Actually, it's the Return on investment (ROI) that matter in business. Or in other word, how many time it'll take to make enough profit to cover the cost of the initial investment. And in this case, the US$9.95 billion California High-Speed Rail is a huge example on how much money you can make on transportation.
If we take Elon Musk word, the ROI of the Hyperloop beat the crap out of any High-Speed Train project. But there's another term really important here, something we call Manufacturing Readiness Level (MRL). Basically, this level told how much maturity a technology have reach. While HST is really high, Hyperloop on the other hand have a MRL really low. Meaning that nothing is proven about the real ROI of the Hyperloop and a huge R&D cost is needed to raise the MRL.
What I love about this is that they raised a sort of huge "kickstarter" to cover the cost of the R&D and raise the MRL to give us a real idea on the ROI of the Hyperloop. Only then we'll have an idea if Hyperloop will revolutionize the transport industry or not.
Elok
Just like North Haverbrook, Ogdenville, and Brockway.
What I'm interested in about the hyperloop is that unlike airplanes, high speed rail and traditional tube is that in the concept you'll have 6-8 passengers/capsule and 3 capsules/train = 18-24 passengers/train, which hopefully means you can have many more dedicated routes and/or a mix of long-hop/short-hop routes using the same infrastructure that'll serve the whole 3000 miles and not just the endpoints.
Around here the train is used for a lot of regional travel instead of bus, shorter than airplane and every time there's talk of building out high speed rail the problem is that it'll actually serve the regions worse since you don't have time to stop, so effectively you're just building a grounded airline. It's a lot easier to find 20 passengers going somewhere at the same time than 400-800 so that could be a major game changer if the technology works out.
Live today, because you never know what tomorrow brings
It’s not a proof of concept, or a scale model. It’s the real deal. "It’s not a test track," CEO Dirk Ahlborn says [...]
Instead, this first prototype will test and tweak practical elements like station setup, boarding procedures, and pod design. [...] It’s also a way to prove that yes, this thing can be built.
Way to contradict yourself... Twice. Emphasis mine.
CLI paste? paste.pr0.tips!
Branching would be really tricky, but there's no physical barriers. Note that even Musk's proposal isn't as far as you can take the concept. If you fill the tube with very low pressure water vapor instead of very low pressure air (via more pumping to overwhelm leaks, plus water vapor injection), your top speed jumps 40%. Fill it with hydrogen and it jumps 300% (normally hydrogen is a real pain to work with due to flammability, embrittlement, etc, but the densities in question are so low that such issues are mostly avoided). So we're talking the potential for hyperloop "speedways" for long distance runs that could blow airplanes out of the water.
The low numbers of passengers per capsule is really key to making the concept economical. Compare, say, monorail track with a full sized rail bridge. The former is vastly cheaper per unit distance because the peak loadings are so much lower, because the mass of the monorail trains are so much lower. A computer-controlled high launch rate of small, high speed capsules means you're spreading the loading out greatly, which means greatly reduced loading and thus materials costs.
Still, while Musk has been thinking of Hyperloop stations in the "airport" concept, he really needs to get out of that mindset. His proposed plan had them on the outskirts of cities. Airports are only on the outskirts of cities because they *must* be. You greatly reduce your utility by doing that, by making people catch connecting trains. Hyperloop can extend just fine into towns; with his two proposed endpoints in particular there are excellent rail routes into town that are quite straight that it could be built over.
You know when it's okay to shout fire in a crowded theatre? When it's on fire.
And if you read TFA, they say they'd need 100+ miles of hyperloop to get you up to the high speeds envisioned. So what you've got is capsules moving groups of people through a tube relatively short distances, at relatively low speeds, and that's all you're likely to see at ANY time from this company and project.
Shit, if only somebody had thought of that when designing ANY MODERN CITY... they could have built it underground, and call it a "sub-way" or something clever like that. I don't know, I'm not good with names, I'm just an idea man.
What this is is some company going, "let's piggyback on Elon Musk's flair for getting publicity and call our subway something fancy that'll capture the imagination of literally hundreds of nerds around the world."
Actually, it's the Return on investment (ROI) that matter in business. Or in other word, how many time it'll take to make enough profit to cover the cost of the initial investment. And in this case, the US$9.95 billion California High-Speed Rail is a huge example on how much money you can make on transportation.
Using the $56 million per km quoted on California High-Speed Rail as the low estimate of how much it would cost to build a hyper loop, the minimum cost across the US would be $56 million per km * 3000 miles * 1.6 km per mile = $270 Billion dollars MINIMUM. That's going to have a hell of a long ROI, and because of that I can't see anyone in their right mind financing such a project in the near future.
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Yeah, and if you just fill it with hot nuts, nobody will ever go hungry. And if you just fill the tube with astroglide, you've got a non-stop party.
Aside from the MASSIVE infrastructure costs of building the actual infrastructure that planes don't need. Planes need a start point, and an end point, and a lot of open space between the two. Luckily, we have lots of free open space in the sky above us at all times, and you don't need .
Hyperloop requires track to be built to every location you want to serve directly enough to make a "ride sharing" type of arrangement as you're describing economical. When only 50 people per day want to go to a given spot on the map, maintaining miles of track to service that means the average ride is going to be VERY expensive. Hyperloop doesn't lend itself well to replacing roadways - it lends itself to replacing the airplane or high speed train model, where you have limited stops, but move very quickly between each stop. Given that, it's almost never going to be more economical than airplanes, and it's doubtful it'll even be as "economical" as the heavily subsidized rail service people like to clamor for, and then not use.
Where passengers can spin around the universe until the end of time.
monorail! Monorail!!! MONORAIL!!!!
Actually, it's the Return on investment (ROI) that matter in business. Or in other word, how many time it'll take to make enough profit to cover the cost of the initial investment. And in this case, the US$9.95 billion California High-Speed Rail is a huge example on how much money you can make on transportation.
Using the $56 million per km quoted on California High-Speed Rail as the low estimate of how much it would cost to build a hyper loop, the minimum cost across the US would be $56 million per km * 3000 miles * 1.6 km per mile = $270 Billion dollars MINIMUM. That's going to have a hell of a long ROI, and because of that I can't see anyone in their right mind financing such a project in the near future.
Did Musk ever propose transcontinental hyperloops? I don't believe he did. As I recall this was always intended as a regional transportation technology, something for distances short enough that air travel is inconvenient because of the airport delays at both ends, but long enough that traditional train travel is too slow.
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Concord is a grape. Concorde is a plane. Concordes was a Montréal football team. Get it right, nerd.
You're missing the point of the Hyperloop and of high-speed rail in general: it's not intended to replace passenger airplanes entirely, only for short and medium distances. The Hyperloop proposal was made as a cheaper, faster, and more efficient alternative to the Los Angeles - San Francisco high speed rail that they've been working on for years now and is costing in the tens of billions of dollars. No one ever said anything about Los Angeles to New York, that would be ridiculous.
Did Musk ever propose transcontinental hyperloops?
No, but the OP did, in an argument comparing planes to hyper loops.
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I made a mistake about the cost of California High-Speed Rail, it's actually $68.4 billion for a the things as of 2011 estimate. Sorry about this.
Elok
Well at first, Hyperloop is aimed as a competitor to "regional airlines" and high-speed train. But if the Hyperloop is as cheap than what Elon Musk is thinking (about 1000% cheaper than HST), we can seriously consider coast-to-coast as a possibility.
Elok
Don't forget the infrastructure, which at some point, just like airports, will come directly out of taxpayer pockets.
Branching would be really tricky, but there's no physical barriers.
I wasn't talking about branching at (full) speed, just how effectively you can insert/extract trains from the loop though I suppose low speed exit/merge tubes could be built. Say you have stations 1-5 connecting two major cities with suburbs at 2-4, could you effectively have a schedule like:
1-5 express
1-5 express
1-5 express
1-5 express
1-4, same time 4-5
1-3, same time 3-5 (and maybe 3-4 local following)
1-2, same time 2-5 (and maybe 2-3 local following)
(pause long enough for train to get out of way at station #2
1-5 express
etc.
Then it would be a real boon to the people living at #2-4, because I think the "every 30 seconds" is to get volume up, I don't think it's very significant if you have to wait 5-10 minutes for your route to come into rotation.
Live today, because you never know what tomorrow brings
I hope Elon Musk isn't getting arrogant, with the push into communication satellites, and hyperloop. The size of the hyperloop vehicles, suggests that it will have a lower capacity than a high speed rail line.
If a high speed rail line wanted to, it could run the long, double deck high speed trains from Japan, that can carry ~1,600 passengers, every 3 minutes. Multiple trains could be stuck end to end. No intercity route in the world needs that kind of capacity. How many passengers per hour will this hyperloop carry at peak capacity?
How much will this yet, unbuilt thing cost?
I the cost of California High-Speed Rail, it's actually $68.4 billion for a the things as of 2011 estimate
As far as I can make out, the Hyperloop is a High Speed Railway inside a tube that structurally can take a vacuum. Plus things like airlocks to get in and out, and some very clever safety measures to allow people to escape in an emergency.
Yes, that has got to be cheaper than just a High Speed Railway, hasn't it?
$56M doesn't really apply here, even if we were talking about a transcontinental hyper loop. I don't know if you've ever driven across the country, but there is a whole lot of empty space. Building stuff there is significantly cheaper than where stuff already exists.
Maybe Musk thinks you can build a tube for less than $1422/inch ?
Only an American could up with this arrogant bullshit. Concorde was stopped because it exploded a couple times and the public lost faith in it, besides being banned from using most routes because of the sonic boom it produced. Does your education teach you about anything except the USA is (supposedly) number one at everything, it's pathetic.
Yes, that has got to be cheaper than just a High Speed Railway, hasn't it?
Is CHSR a government project?
In which, yes, it probably will be a lot cheaper.
Yeah, that's right, satire!
systemd is Roko's Basilisk.
The usual way to determine if a project is making money is to subtract operating costs and the amortized portion of construction costs from operating revenue - and to date the unbuilt California High-Speed Rail system has precisely zero operating revenue. It's projected to make money (according to it's backers), but projections aren't revenue.
Just because it's in TFA doesn't mean it's right. At the same maximum acceleration of a Tesla Model S (1g in "insane" mode), you need 3.6 miles to get up to full hyperloop speed. If you want to take 100 miles to do the same thing, you're talking about 0.04g, which is absurdly slow. That acceleration would give your car a 0 to 60 time of 75 seconds...
There's no need to accelerate that absurdly slow. Cars, airplanes, trains, they all accelerate much faster than that. On the other hand, if their 100 miles includes the distance required to decelerate...
Sure, because the cost of materials has little to do with the cost of building a highspeed railway. You've got a mighty wide right of way, and you need to buy a huge amount of land for that, plus there's a ton of labour to prepare that right of way, clearing it of all obstacles, leveling the terrain, installing the track, the filler, etc.
The hyperloop could theoretically end up cheaper because it requires a smaller right of way with much less labour to install. The cost of materials would be higher, but the huge reduction in land requirements and labour could potentially counteract that.
The hyperloop uses low pressure air because the design assumes there will always be lots of leaks, which can be overcome by the pumps. Air will always be leaking in, so you just pump it back out. And because it's not a vacuum, the pumps aren't as insane as they'd need to be to maintain a hard vacuum.
As soon as you start talking about putting anything but air in the thing, then that whole idea goes out the window, you now need to go from "mostly airtight" to "completely and utterly airtight", and everything gets incredibly difficult.
unlike airplanes, high speed rail and traditional tube is that in the concept you'll have... 18-24 passengers/train, which hopefully means you can have many more dedicated routes and/or a mix of long-hop/short-hop routes using the same infrastructure that'll serve the whole 3000 miles and not just the endpoints. ........It's a lot easier to find 20 passengers going somewhere at the same time than 400-800 so that could be a major game changer if the technology works out.
But then you will need to wait around until 19 other passengers turn up who want to make the same journey as yourself. Also, running trains of such low capacity severely limits the total capacity of the line (and hence the payback) because the trains must be kept a minimum distance from each other (at least the braking distance).
Trouble with mixing long-hop and short-hop on rail (we call them main-and-local or fast-and-slow in the UK) is that the local train stopping holds up the "fast" train behind, so in the end they all might as well stop at all stations. That is what metro lines generally do. Another approach is to have stopping loops at each station so that the fast train can overtake the local, but that can lead to long waits for the local before leaving stations (think about it). British Railways decided to abolish most intermediate stations and local trains on non-suburban lines in the 1960's.
The best solution is to have multiple pairs of tracks for different types of train. There are basically six tracks (ie three pairs) from Euston (the main London terminus for the North-West) for the first 16 miles though the suburbs, and then reducing to four.
$56M doesn't really apply here, even if we were talking about a transcontinental hyper loop. I don't know if you've ever driven across the country, but there is a whole lot of empty space. Building stuff there is significantly cheaper than where stuff already exists.
A 4 lane highway in rural areas costs about $5 million per mile (*). And while a road is not an enclosed vacuum tube, the vacuum tube would be many more times complex to build (and maintain) than the road - for example, there its the infrastructure needed to keep the hyperloop pumped down to its working pressure, as you can be sure that leaks will occur.
But that infrastructure will have to be dispersed across the length of the hyper loop, as a pumping station in LA or NYC will not be able to deal with a leak in the midwest until the air introduced in that leak makes its way to either end of the loop - meaning both a huge volume of air, and a huge lag time until it gets there. And huge vacuum pumps will not be cheap, and will have to be powered by something. So there you are building not only the hyper loop, but at a minimum HV transmission lines for the pumping stations and possibly power stations as well (be they solar, wind, nuke or coal), as well as the roads needed to reach that infrastructure . Plus as you say .. you are doing it in the middle of nowhere,which is going to jack up prices in its own way.
So it does't take much for the cost per mile to start adding up.
* $5 million per mile cost for a 4 lane highway is taken from the American Road & Transportation Builders Association website. And it rises to $9 million in urban areas.
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It also depends on the cost of the alternatives. The California Highspeed Rail from SF to LA, currently under construction, is projected to cost $500,000 per seat to build. Even if the ticket prices are heavily subsidized (and they will be) they will have to be very high to recover that expense.
Are you dumb? Really, seriously that dumb?
1) No mass transit is going to accelerate at 1g. Takeoff thrust for a plane is ~.3-.4g, depending on the plane.
2) Of COURSE they're taking braking and deceleration into the equation - no transit system is all that useful if everytime you get a passenger to ride it, you slam them into a brick wall at the end.
3) There's a lot more force required to accelerate a metal capsule containing 6-8 people than there is required to make a small, lightweight sports car move fast with 1 or 2 passengers. The higher the acceleration, the more energy required; the more energy required, the more expensive your system is.
What *this system* is talking about is the equivalent of a train car on an elevated track. Perhaps Chicago should rebrand the L as a Hyperloop, too, and reap the nerd cred.
I take a lot of that back. Apparently I know fuck all about what a hyper loop actually is. It is not a hard vacuum at all.
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"couple" of times? Say what, dumbshit? The public COULDN'T AFFORD it!! Plenty of normal planes blow up, people still fly in them!
You total fool!
I just cannot see how a large tube holding a vacuum extending 100 miles or 300 miles or 500 miles or 2,800 miles is ever going to be cheaper than a rail track the same length (assuming right of way problems can be solved--and note the high speed rail system between SF and LA had to be slowed down because right-of-way issues put too many curves in the track) is ever going to be cheaper per passenger mile. And if it turned out per passenger mile a train was cheaper (without government subsidies) than flying a fleet of 737's, do you think investors in their right mind would fly a fleet of expensive 737's when they could run cheaper trains?
And one thing people forget when counting the cost of using trains to transport people or goods is the fact that the first railroads which connected the U.S. continent was built on the cheap with slave labor.
Hope they remember to put the station at the top of a small hill to save having to do much breaking and acceleration.
The HyperLoop Elon proposed was estimated to cost 1/10th of the LA-SF CHSR project, but it only had 1/10th of the capacity.
Unlike the CHSR project, the proposed HyperLoop project actually only connected the outskirts of LA to the Oakland bay, leaving out the expensive part of going to downtown LA and downtown SF.
The estimated HyperLoop projects assumed they save on expropriations by placing the track elevated over existing highways.
But to travel at 800 mph without making your passengers sick and barfing, the route actually needs curves to be 16 times as smooth as the 200 mph CHSR.
The estimated HyperLoop costs were low by an order of magnitude even when comparing to known costs of elevated track and even of oil pipelines. Let's not even talk about the actual precision needed to make this work at 800 mph.
Well, construction costs should be lower than rail thanks to pylon's dramatic reduction in necessary ground preparation per mile, and the technical simplicity (it's just a big, airtight pipe after all), and it should be dramatically faster than commercial planes, as well as being much cheaper to operate. Bigger up-front costs, but only minor operating costs, and the operating costs are the vast majority of the expense of airplanes.
It is still very much a "point to point" transportation system, which does limit it's usefulness, but high speed rail pales in comparison, in terms of both speed and construction cost. If you assume a decent bus/monorail/commuter train/etc. system ties in to the same down-town transportation hub as the Hyperloop, it should be extremely feasible - might even provide endpoint cities the incentive they need to build public transportation systems that are worth a damn. Or perhaps it just hosts a thriving Zipcar station.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
The first US transcontinental railroad was built primarily by low-paid Irish and Chinese immigrants and veterans from the Civil War. Since it didn't go through any slave states, at no point did it involve any slaves (at least in any significant number). Though how "free" the immigrants were is probably debatable.
As for your inability to see how a tube could be cheaper than a rail track, you can always just read the proposal. The hyperloop was specifically suggested as an alternative to an existing rail project, in part because it would be cheaper, so the comparison is there. Whether it's correct or not is another question.
For any given leg of the journey you probably want all the trains traveling at the same speed, as set by the long-haul trains - there's no passing lane in the tubes after all, and a train going 800+mph covers an awful lot of ground in 30s. If you want to make a 15 minute trip by 200mph train, you've just backed up the 800mph trains for an hour. So any switching would have to be at roughly full speed - once on a side loop you could then do whatever you want of course. And the linear accelerators are likely to be a significant fraction of the total cost - it takes many miles to get a train up to 800mph, the rebooster stations just give them a little speed bump, and every station would need it's own quad of zero-to-full-speed accelerators (one each braking and accelerating for both directions)
There is however the possibility of putting more than 2 tubes on the pylons - once the right-of-way has been acquired and the pylons erected there no reason you couldn't have both a 2-way pair of high-speed tubes, and a second pair of low-speed tubes all suspended from the same pylons. The tubes themselves are after all probably only a fraction of the total cost, and having a second pair of tubes would also offer redundancy when inevitable downtime is necessary for one of the others.
Then if you wanted to get really fancy you could periodically have multi-mile "switching stations" to accelerate cars from one tube to the other
--- Most topics have many sides worth arguing, allow me to take one opposite you.
The US Department of Transportation spent at least $50M on road infrastructure each of the past two years. So not as long as you lead us to believe.
Rail needs an extremely expensive foundation, and right-of-ways. Hyperloop requires occasional pylons, radically reducing the ground-level expense. And it's not like the tubes themselves are high-tech, it's just a bunch of sturdy, reasonably airtight tubes - size large urban water pipe would probably do the job fine with a little cable suspension to support the lengths between pylons.
--- Most topics have many sides worth arguing, allow me to take one opposite you.
High speed railway is *phenomenally* expensive. It requires massive earthworks because of the very limited turning radius and limited climb angle of high speed trains. It requires very specialised rails that have to be laid under very high tension and welded so that the result is seamless and can withstand large temperature variations. It's also much more expensive to ballast because normal ballast doesn't cusion things well above certain speeds and turns into nasty pebbles instead of spikey lumps of rock. The result is big and heavy which means it needs its own strip of dedicated land. Finally, the air resistance for high speed rail grows quickly. On the very high speed test trains it gets comparable to aircraft. Despite having a smaller frontal area per passenger mile, the trains go fast in the thick lower atmosphere. The costs of those things add up a lot.
The hyperloop system claims to solve some of them and long, large airtight pipes are also well established technology in the oil industry for pipelines.
Whether or not the hyperloop claims are valid, I don't know, but it's not as wild as it first seems.
SJW n. One who posts facts.
But to travel at 800 mph without making your passengers sick and barfing, the route actually needs curves to be 16 times as smooth as the 200 mph CHSR.
You can save some by using tilting trains: they can go around much tighter curves at speed than regular trains with a low barf-factor.
SJW n. One who posts facts.
The usual way to determine if a project is making money...
Government projects are the only enterprises less subject to the ordinary methods of determining profit than tech startups.
Failure to follow this advice may result in non-deterministic behavior.
And you have a background in Civil Engineering that lets you understand this? Or are you just hand-waving like Mr. Musk and saying "somehow it'll be cheaper"?
how do you figure? You think keeping hundreds of miles of tubing is really going to be cheap? Go look at a highway budget sometime. Then consider that this highway needs to be enclosed, and maintained in such a way that air leaks are minimized. Then consider that you have to have a way to create low pressure inside miles and miles of pipe. Then consider that you have to pump the energy for maintaining your low pressure interior and propelling and braking the capsules through the system. Then consider what's going to happen to your ENTIRE system the first time a piece of the pipe ruptures or becomes blocked by an accident. Then consider how you're going to a) locate and b) extract all of the thousands of people "somewhere along that pipeline" when the entire system has to be shut down for repairs for a few days.
Anybody who thinks this is going to be cheaper and easier to keep running than a train line or a roadway is insane.
And here in America, rail travel in general - outside of metro subway systems - is considered pretty much a non-starter. It barely survives, and it's crappy service. That should give you an idea of the small number of people who will be lining up to ride the hyperloop - if trains were a "decent" alternative, then it would already be successful - it's not like they haven't been around for years. Hyperloop offers a 'slightly cheaper' alternative to a service that nobody really wants.
Spare me the "if you build it, they will come," argument too - How busy is the Acela service between Boston & DC? (Hint: not very.)
I haven't read their web site. How much do you want to bet a big part of their business model is to set up an HOA? Yeah, I'm really eager to get shot out of an experimental cannon and pay extra taxes for the privilege.
OK... now I look at the web site. No mention of the HOA; but I would still be really surprised if it isn't in there. It's probably not disclosed until you're deep into the sales process, and then they gloss it over and lull people into thinking it's just how things are and not a big deal. Trust me. It's a very big deal. Beware of developers building "sustainable" cities. They are scuz bags.
If you were simply overpaying for all the features they proclaim, that'd be bad enough. It's worse though. You won't even get half the features they mention. You *will* get the petty politics and financial mismanagement of an HOA. Those things on the web site do not build themselves.
You can also tilt the track, canting in railway terms.
Canting in normal railway lines is limited due to the need to handle slow trains, but on high speed rail it's often allowed to be higher.
That's why it's uncommon to use tilting trains above 250 km/h: it's usually preferable to tilt the track than to increase the weight of trains by adding tilting systems.
Though the Japanese have some.
That said, "much" is a relative statement, Whether you tilt the train floor or the track the accelerations experienced by the passenger
- lateral: is v^2/r - g*sin(tilt_angle); acceptable limit is +/- 0.1g
- vertical: 1g + v^2/r * cos(title_angle); limit is 1g+/-0.05g, IIRC
As you can seen from the math, the problem increases with the square of speed, while the benefit from tilt is is limited and bound by the need to keep both lateral and vertical acceleration within bounds.
Branching would be really tricky, but there's no physical barriers. Note that even Musk's proposal isn't as far as you can take the concept. If you fill the tube with very low pressure water vapor instead of very low pressure air (via more pumping to overwhelm leaks, plus water vapor injection), your top speed jumps 40%. Fill it with hydrogen and it jumps 300% (normally hydrogen is a real pain to work with due to flammability, embrittlement, etc, but the densities in question are so low that such issues are mostly avoided). So we're talking the potential for hyperloop "speedways" for long distance runs that could blow airplanes out of the water.
Branching at full speed is probably not possible with the Hyperloop as designed; the skis are curved to match the diameter of the tube, with a ~1mm clearance with the tube surface, so there is no passive tube design that could accommodate a "switch". In order to continue from Section A to either Section B or Section C, you'd have to make an intermediate length of tube several hundred meters long that could be physically moved at one end from B to C, with sub-millimeter precision, with the entire thing enclosed in vacuum. By the time demand is great enough to warrant branches, it's probably more cost-effective to make a dedicated parallel tube than to re-purpose a single tube with a ridiculously complicated switch. Hydrogen (or water vapor) would be most helpful in reducing Kantrowitz effects near the sound barrier, but not necessarily in enabling higher absolute speeds. The reason is threefold: drag continues to increase at higher speeds regardless of the speed of sound, lateral acceleration increases with the square of velocity, and the vertical precision of the pipe also improves with the square of the velocity. If you consider that the steel Hyperloop pipe draped across 30m-spaced pylons will approximate a vertical sine wave, then at 700mph the allowable sag is only about 5cm between pylons before the capsule's vertical suspension is overwhelmed and it starts "bouncing". (Assuming the mass of the skis/suspension is 10% of the capsule mass, so it can accelerate vertically at 10g to keep contact with the track.) At 1500mph, the tube requires a vertical precision of 1cm between 30m-spaced pylons, and its trajectory would have to be ridiculously straight to avoid problematic lateral g-forces. Mechanical braking from 1500mph in the event of an emergency is also a non-starter; 700mph is right at the edge of what can be feasibly done without melting brakes or destroying the tube. And in the event of a rapid tube repressurization, a 700mph capsule will incur about 2g's of aerobraking deceleration; at 1500mph it would experience about 10g's, likely enough to destroy the capsule and/or kill the passengers.
Weeks of coding saves hours of planning.
The hyperloop uses low pressure air because the design assumes there will always be lots of leaks, which can be overcome by the pumps. Air will always be leaking in, so you just pump it back out. And because it's not a vacuum, the pumps aren't as insane as they'd need to be to maintain a hard vacuum.
As soon as you start talking about putting anything but air in the thing, then that whole idea goes out the window, you now need to go from "mostly airtight" to "completely and utterly airtight", and everything gets incredibly difficult.
You could do a mixture of air with other gases, and gain many of the advantages while still avoiding a hard air vacuum. For instance, 50Pa air + 50Pa water vapor, or even 50Pa air + 50Pa H2. A promising approach would be for the capsules to store on board some of the air they're compressing anyway, to help maintain the tube pressure. The alternate gases could even be added as part of the cooling system; if liquid nitrogen or liquid hydrogen were injected directly into the compressed air stream to cool it, it would greatly reduce the need for water intercoolers and onboard steam storage, increase the available pressure to the skis, and be balanced by onboard storage of some of the compressed air stream. And the pressures are low enough that combustion shouldn't be a problem, even with H2. Vacuum leaks are most likely to come from two sources: the end station airlocks, and the capsules themselves. Most of the tube is just Big Dumb Pipe (tm), which really shouldn't leak. And 100Pa is really not too difficult to maintain; the volume of the entire LA-SF Hyperloop tube is equivalent to a cube about 130 meters on a side.
Weeks of coding saves hours of planning.
Every survivor gets a free plastic action figurine.
" its the cost per passenger mile that matters. "
Agreed. Hyperloop is cheaper per passenger mile for the right distance and locale.
"And a large airplane traveling along at 500 miles per hour ..."" ...spends an enormous amount of energy pushing air out its way and climbing to altitude. In addition to the $300 million cost of a new jumbo, brought on by stringent aviation regulations and security, include the cost of building these enormous airports all over continents, the cost of shutting it all down for hours and days in inclement weather, the cost of travelling to a necessarily large airport away from the city for each flight.
With all those costs accounted for, Musk et al still acknowledge that air travel is preferable for transcontinental travel, but not for the ~300-800 mile trips. In that range Hyperloop easily wins on cost per passenger mile, and at least has the option of doing so without hydrocarbons.
But to travel at 800 mph without making your passengers sick and barfing, the route actually needs curves to be 16 times as smooth as the 200 mph CHSR.
The Hyperloop will bank freely like a bobsled; the passengers will experience virtually no lateral acceleration. (The same is true of an airplane in a tight bank.) This will make the ride far less barf-inducing. The lack of turbulence will also help greatly.
Weeks of coding saves hours of planning.
$98 billion per the LA Times, making CA HSR the most expensive and slowest HSR project in the world. Ta-da!
http://articles.latimes.com/2011/nov/04/local/la-me-high-speed-rail-20111104
$500k actually sounds pretty cheap per seat. Even the lowest estimate of use put forward by critics of the project was 23M passengers/year. To pay for construction in the first year each passenger would need to generate $43 in profit over running costs. Realistically they could charge much less and still turn a profit in a reasonable time.
Japan is currently building a maglev high speed "rail" line between Tokyo and Osaka. 86% of it will be tunnels through extremely challenging terrain. Initial speeds will be 550km/h, rising to around 900km/h in time so somewhat similar to the hyperloop proposal.
The cost in very, very high. Far higher than what the US is paying. It's new technology and it's difficult terrain. The pay-back time is going to be long. Decades before it shows a profit. The thing is, Japan Rail is in it for the long haul. That line will be running indefinitely. The current ones started in 1964, more than 50 years ago. The tickets are reasonably priced and the volume of passengers will be high. It's much, much faster than flying and much, much cheaper. The technology itself is valuable, and will be exported to other countries.
Oh, and pollution is much lower and from flying. It's safer too. There really is very little not to like.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
'the Hyperloop is a High Speed Railway"
Nope. Rail is heavy and thus mostly must reside on the ground and thus takes up a right of way along hundreds of miles which cuts everything in half along its path and hampers if not stops any traffic along its path. HSR in particular will require fencing along the route.
Hyperloop is an elevated pipe which, like transmission lines, largely does not interfere with the land underneath and thus the right of way is far cheaper than that for rail or roads. Hyperloop is also three or four times faster than HSR, and immune to weather, animals that dig there way on to the tracks, etc. So no, Hyperloop is not a High Speed Railway.
Take a look at the wikipedia entry for a city. It's just a plan and the plan for the city is being nixed already. There's never going to be a hyperloop there.
As I wrote in the another post[1], you need to limit both lateral and vertical accelerations, which puts constrains on how much you can get from banking.
Eg, if you bank almost 90, the passengers will experience no lateral acceleration, but they will experience vertical acceleration, for which tolerance is even lower.
At 800 mph, even the sloping the line up/down will be a problem.
This is all well understood and researched, as it's a massive and expensive problem for all modes of transportation that go at least as fast as a car in a highway.
The Hyperloop proposal simply glossed over reality in this aspect, along many others.
[1] http://tech.slashdot.org/comments.pl?sid=7030445&cid=49155263
But to travel at 800 mph without making your passengers sick and barfing, the route actually needs curves to be 16 times as smooth as the 200 mph CHSR.
Some critics of the Hyperloop concept have focused on the possibly unpleasant and frightening experience of riding in a narrow sealed, windowless capsule, inside a sealed steel tunnel, that is subjected to significant acceleration forces, high noise levels due to air being compressed and ducted around the capsule at near-sonic speeds, and the vibration and jostling created as the capsule shoots through a tube that is not perfectly smooth or level.[25] Even if the tube is smooth upon construction, ground shifting due to settling and ongoing seismic activity will inevitably cause deviations from a perfectly smooth, level path. At speeds approaching 900 feet per second (270 m/s), even 1 millimeter (0.039 in) deviations from a straight path would add considerable buffeting and vibration. With no provisions for passengers to stand, move within the capsule, use a restroom during the trip, or get assistance or relief in case of illness or motion sickness,[26] the potential for a seriously unpleasant travel experience would likely be higher than in any other popular form of public transport.
- Wikipedia
"Total destruction the only solution" - Bob Marley
Actually, high speed rail can climb much better than regular trains.
And a lot of your other issues are likely going to face hyperloop as well. The pipes used by the oil industry will not be suitable for hyperloop (they certainly aren't moving oil at high speed, plus it is self lubricating), the tolerances required for a capsule running at 800mph are going to be significant. Hyperloop will also require a "big" strip of land, or equally significant tunneling, because you are in essence replacing the big train with a still reasonable big capsule.
It may work, and it may well offer significant cost savings, but it can also just as easily be just as expensive or not work at all.
1) No, but you're talking about acceleration rates (if it takes 100 miles to hit full speed) that are half that of a high speed train, despite not needing to carry your motors or power (for acceleration with you). There's no reason to be accelerating that slowly. Aircraft, as you point out, accelerate much faster, and passengers tolerate that just fine.
2) A full system would require that, as would a test track, but the article merely said they needed that much track to get to full speed. It didn't qualify if that included deceleration.
3) Except the hyper loop capsules are far smaller than high speed trains, and their acceleration rate would hit hyper loop speed in 50 miles. The hyper loop uses linear accelerators in the tubes themselves, so power isn't really an issue: you can accelerate the vehicle at whatever speed you want, passenger comfort is the limitation.
Also, the hyper loop is not equivalent to a train car on an elevated track. Because it's not a train, it's a ground effect aircraft in a partially evacuated tube. It makes no physical contact with the walls. If anything, it's closer to a maglev train than a regular train.
"The higher the acceleration, the more energy required;"
No, the more power required. Energy is power * time, and the acceleration period for a HL pod is a few tens of seconds, versus hundreds of seconds for an aircraft. For example, 30s to reach ~700 mph at 1g, or 1 minute at 0.5g, etc.
"is the equivalent of a train car on an elevated track."
No. The mass per unit length is a couple orders of magnitude lower than an elevated rail or road project. The better analogy is an elevated pipeline, like the Trans-Alaska pipeline, which has a price per mile more inline with the pipe and pylon costs given by Hyperloop.
'The hyperloop uses low pressure air because the design assumes there will always be lots of leaks, " No, the primary reason for hyperloop low versus hard vacuum is to enable the pressurized air suspension of the pods. Also, pumps for soft vacuum are far cheaper than hard.
"unpleasant and frightening experience of riding in a narrow sealed, windowless capsule, inside a sealed steel tunnel, ... potential for a seriously unpleasant travel experience "
Like an airplane traveling at night for ten hours in rough weather or turbulence from the aircraft 10 miles ahead for most of the trip? Hyperloop SF to LA will be 30 mins. I suspect people can avoid the restroom.
"ground shifting due to settling and ongoing seismic activity will inevitably ..." ... will inevitably be addressed by load levelers between pylon and the tube, as they have been for years for all kinds of structures.
Passenger aircraft commonly bank at up to 30, which is a vertical g-force of 1.15g. The Tesla Model S P85D accelerates off the line at 1G longitudinal, for a combined g-force of about 1.4g. The Gravitron (common at carnivals) pulls 3g's continuous. Roller coasters commonly pull 4-5g's for short times. (though admittedly, that can be barf-inducing.) The Hyperloop is designed for a maximum combined g-force of 1.4g, corresponding to a 45 banking angle. With reclining seats, this should feel similar to a Model S accelerating off the line, and should be easily tolerated. The key consideration will be to minimize "jerk"; abrupt changes in acceleration. So the curves will have to be designed so the banking radius changes gradually rather than abruptly. No doubt there will be people who are intolerant of the Hyperloop, just as there are people who are phobic/intolerant of air travel. Perhaps there could be a designated "slow hour" where the capsules are run at 3/4 speed to reduce the g-forces. But with appropriate warning and visual feedback provided, I think most passengers would quickly get used to it.
Weeks of coding saves hours of planning.
50Pa air + 50Pa H2....>
That's 1/5 a ton of H2 in a 381 mile cylinder, which has to be replaced every time there's tube service. What advantage obtains to warrant H2 handling? Any drag advantage obtained by the capsule has to made up with more compression to move more mass for the air skids.
The main advantage to hydrogen would be overcoming the Kantrowitz choking effect caused by supersonic flow; this is one of the most significant design constraints of the Hyperloop. Increasing the speed of sound (by mixing the air with hydrogen) increases the speed at which the ambient gas can flow around the capsule, greatly reducing the pressure that builds up in front at a given speed. Hydrogen is cheap; liquid hydrogen can be had for less than $1/kg, so cost is a non-issue.
Another design constraint of the Hyperloop is cooling the compressed ski air. The Alpha design calls for a 300kg water tank and intercooler, flash-heating the water to steam and storing it in "steam tanks", the complications of which are swept under the rug. (300kg of water would become 500 m^3 of steam at 1atm, several times the volume of the capsule itself.) By injecting liquid H2 into the air stream to cool it, the need for the intercooler and steam tanks would go away. Hydrogen has an exceptionally high specific heat; liquid hydrogen is extremely effective at removing heat from a system. Some of the compressed air + H2 could be further compressed and stored onboard the capsule to maintain the tube at 100Pa, or perhaps the excess H2 could be handled by placing adsorbent material (e.g. activated charcoal) in the tube to soak it up, and replacing/recharging this material at intervals. Since hydrogen moves so fast, placing the adsorbent material only at the endpoints might be sufficient.
Weeks of coding saves hours of planning.
Allowing the air pressure to equalize inside, or am I just a pessimist...
While remote and nothing like along side I5, the Alyeska pipeline sees many. These are the search results for: rifle shots in alyeska pipeline http://preview.tinyurl.com/mtu...
Branches don't have to be that complicated. As long as the skis can move around the diameter of the pod, the following solution would work: Have a second tube gradually drop out of the bottom of the main line tube. If the pod skis are further apart, the pod would continue in the mainline -- if the skis are closer together, the pod would continue into the lower tube. This would need to be a gradual process - so a stretch of track a mile or two in length. I'm sure there are other engineering solutions.
English isn't keeping up with agile development.
This is one of those "yes/no/shrug kinda but not really" situations. It's not like a 1900s ship launching where it was a binary float or sink. But it's also the first of it's kind at that scale. But we have computers and models. And so on and so forth.
And in the event of a rapid tube repressurization, a 700mph capsule will incur about 2g's of aerobraking deceleration; at 1500mph it would experience about 10g's, likely enough to destroy the capsule and/or kill the passengers.
That kind of deceleration assumes an instantaneous transition from 100 to 100000 Pa, which is not possible absent total destruction of the tube immediately prior to a pod at cruise, in which case deceleration due to air is moot. Otherwise the pressure in a 381 mile long tube must rise gradually.
Keep in mind that these quotes are all excerpted from articles by bloggers, not engineers. The skis connect to the capsule through a hefty suspension, so minor bumps won't be transmitted to the passenger compartment. There will be no lateral acceleration experienced by passengers; the capsule would bank freely like a bobsled, so all banking acceleration will be perceived as vertical (as in an airplane), pressing you down into your reclined seat, thus much less barf-inducing. The noise levels shouldn't be problematic, since the ducted/bypassed air is still at extremely low pressure (2kPa, equivalent to 30km/90,000ft altitude), and can be sonically isolated from the cabin. The airflow around the exterior of the capsule is vanishingly thin, so it should produce hardly any noise at all.
Weeks of coding saves hours of planning.
That kind of deceleration assumes an instantaneous transition from 100 to 100000 Pa, which is not possible absent total destruction of the tube immediately prior to a pod at cruise, in which case deceleration due to air is moot. Otherwise the pressure in a 381 mile long tube must rise gradually.
Ok, let's look at an emergency scenario where a capsule (not the tube) undergoes rapid depressurization. To save the passengers, the ambient pressure in the entire tube must quickly (within a few seconds) be brought up to levels at which oxygen masks will function; about 20kPa. This can be done by flooding the tube with air evenly along its length; no tube destruction required. The question is whether a 20kPa tube atmosphere would impose problematic aerobraking forces on the capsules. At 700mph, you'd probably be ok. But at 1500mph, you'd immediately be exceeding the ambient speed of sound, which would be very bad. (Flooding the tube with a high H2 mixture to keep the speed of sound high would create a very explosive environment, so that's not an option.)
Long story short: if your capsule suddenly depressurizes at 1500mph, you're dead. But at 700mph, you might still be ok. The risks and complexities associated with hypersonic tube travel seem to outweigh the benefits, at least for now. Subsonic is good enough, really.
Weeks of coding saves hours of planning.
The main advantage to hydrogen would be overcoming the Kantrowitz choking effect caused by supersonic flow;
Yes, understood, and any design choice that further lowers the density of gas in the tube requires more compressor work for the air bearings, which require a fixed mass per second flow. From the alpha proposal:
"At nominal weight and g-loading, a capsule on the Hyperloop will require air injection beneath the ski at a rate of 0.44 lb/s (0.2 kg/s) at 1.4 psi (9.4 kPa) for the passenger capsule."
The main advantage to hydrogen would be overcoming the Kantrowitz choking effect caused by supersonic flow;
Yes, understood, and any design choice that further lowers the density of gas in the tube requires more compressor work for the air bearings, which require a fixed mass per second flow.
I don't think that's right. The air bearings function based on pressure, not mass density. 50Pa air + 50Pa H2 would keep the overall tube pressure the same, so the compressors' job wouldn't change. In fact, since the H2 (in my proposed design) would be injected into the ski air stream post-compression, the compressors would have less work to do, not more. The required mass flow to the skis using an air/H2 mix would actually be substantially less than in the Alpha proposal. Again, the pressure is what's important (averaging 7kPa under the skis), not the mass per se.
Weeks of coding saves hours of planning.
...
Ok, let's look at an emergency scenario where a capsule (not the tube) undergoes rapid depressurization. To save the passengers, the ambient pressure in the entire tube must quickly (within a few seconds) be brought up to levels at which oxygen masks will function; about 20kPa. This can be done by flooding the tube with air evenly along its length; no tube destruction required. The question is whether a 20kPa tube atmosphere would impose problematic aerobraking forces on the capsules. At 700mph, you'd probably be ok. But at 1500mph, you'd immediately be exceeding the ambient speed of sound, which would be very bad.... Long story short: if your capsule suddenly depressurizes at 1500 mph, you're dead. But at 700 mph, you might still be ok. The risks and complexities associated with hypersonic tube travel seem to outweigh the benefits, at least for now. Subsonic is good enough, really.
Interesting, and necessary, scenario. But I think the "few seconds" constraint is extreme. At 800 mph the vehicle stops in 30s at 1g, and I suspect 3g (space shuttle launch) is not that intolerable in an emergency; its certainly not fatal. Unconsciousness takes about 15s. There have been vacuum chamber accidents where people have recovered after exposure to vacuum for 30s (i.e. yes, Bowman with no helmet could have beat HAL in 2001).
You know when it's okay to shout fire in a crowded theatre? When it's on fire.
As someone else already mentioned, it uses low pressure air because the "trains" are ground-effect aircraft, not maglev. They need air.
Secondly, the pumping budget to overcome leaks is so small, both in terms of capital and ongoing costs, that you could increase them by an order of magnitude and not have any sort of practical effect on the budget. Whatever factor you increase over the baseline increases the factor you can replace air by. You don't need 100%.
You know when it's okay to shout fire in a crowded theatre? When it's on fire.
First off, if servicing that requires full de/repressurization is some sort of frequent event, then the whole concept is doomed for reasons entirely unrelated to anything in this discussion. Secondly, 1/5 ton of hydrogen at industrial rates is about $200. Whoop-di-doodle-doo. And the advantage is being able to travel at mach freaking 4, not about the reduction of drag at a given speed (which is, FYI, true also).
You know when it's okay to shout fire in a crowded theatre? When it's on fire.
Not only that, but if your craft is travelling four times as fast, you're sweeping through four times as much gas per unit time to compress under the skis.
Hydrogen has all sorts of advantages. And the very low pressures prevent most of the negatives. The only one that I don't know about and would require testing would be what sort of reaction would one see as a craft moves past, with any residual oxygen. If I had to guess, I'd guess that you will get some combustion, but the craft moves past so fast and the mixture will decompress so fast, I would think the rate would be quite limited.
You know when it's okay to shout fire in a crowded theatre? When it's on fire.
Wait, meaning that while it's technically possible, but it'd be really tricky to accomplish? Gee, I wish I had written something like "Branching would be really tricky, but there's no physical barriers" at the top of my post ;)
Drag is reduced in the first place by using hydrogen even at a given pressure. And you can use 1/4th the pressure and still maintain lift because you're moving four times as fast. And given how few reboosts are needed from LA to SF in the base case, a few more per unit distance hardly seems limiting.
Irrelevant because earthquakes impose far more deflection that you have to be able to counter (and that the proposal calls for countering) than a craft moving past.
What, you're picturing drum brakes or something? You're moving at high speeds in a giant steel tube. Magnetic braking couldn't possibly be easier.
Where are you getting this from? Even if the tube was instantly full pressure (which it wouldn't be), a streamlined shape will not experience 2Gs at 700mph, any more than a passenger jet losing full engine power does. And anyway, 10g horizontal is not fatal even if that was the case. The average untrained individual, properly restrained, can tolerate 10g for a minute without even loss of cognitive function.
You know when it's okay to shout fire in a crowded theatre? When it's on fire.
What sort of claim is that? Since when do oxygen masks need 20kPa to function? And secondly, if there's "problematic loading on the capsules" from too much pressure on the pressure-compromised capsule, then your pressure is also way too high inside. Which means that you've repressurized the tube way too much. So the solution is: Don't do that!
You know when it's okay to shout fire in a crowded theatre? When it's on fire.
The 20kPa figure (0.2 bar) is what's required to supply low-altitude-equivalent O2 partial pressure through an oxygen mask, maintaining consciousness, and is what limits commercial aircraft to a 40,000ft (0.2bar) operational ceiling. See: Cabin_Pressurization
Most people will black out if the oxygen partial pressure drops below about 14kPa. A highly conditioned athlete or acclimatized mountain climber could stay conscious with 10kPa for a short time. 7kPa O2 is equivalent to the summit of Everest without an oxygen tank; very few people can survive that for any length of time.
The "problematic loading on the capsules" is from the high speed aerodynamics, not the ambient pressure. The question is whether you can simultaneously get the ambient pressure high enough that the passengers don't suffocate, while keeping the aerodynamic forces low enough that the capsule doesn't disintegrate. This seems to be possible with a 700mph Hyperloop, but probably impossible with a 1500mph Hyperloop.
Weeks of coding saves hours of planning.
And the advantage [of hydrogen] is being able to travel at mach freaking 4, not about the reduction of drag at a given speed (which is, FYI, true also).
Making the Hyperloop go that fast would require an impossibly straight and level track. Even at the Hyperloop's current design speed (Mach 0.99), the maximum allowable vertical sag of the tube between 30m-spaced pillars is only about 5cm. Any more than that, and the air ski suspension won't be able to compensate and the capsule will start skipping and bouncing. At Mach 3-4, the tube couldn't sag more than a few millimeters between pylons before overwhelming the suspension. So for the foreseeable future, the advantage of hydrogen will be that it reduces the problem of choked flow and the Kantrowitz limit at more reasonable (~700mph) speeds. By the time the Hyperloop is commonplace and we're contemplating Mach 4 travel, we'll probably be talking fully evacuated tubes with maglev like ET3. Maglev could probably also deal more flexibly with uneven track height at those speeds. Or Musk could be right in thinking that supersonic air travel is ultimately the best solution for >1000km distances.
Weeks of coding saves hours of planning.
Clever, but probably unworkable given the large cross-section of the capsule relative to the tube. Even on a perfectly straight track (no banking), taking the upper branch would require the skis to "split" wide enough that the entire capsule width would fit between them. Given the Alpha design numbers (ski width 0.9m, tube diameter 2.23m, capsule width 1.34m), the skis would have to split nearly horizontal to avoid the lower-branch "gap", and it's unlikely they could function at such a steep angle. Maintaining the precise shape of a non-circular tube against vacuum pressure is also a very difficult problem.
Weeks of coding saves hours of planning.
Well, there are physical barriers to a static design that allows branching. Actively moving an entire section of tube to reconnect it to a new one is sort of a brute-force approach, and highly unlikely that it would be worth the complexity and risk, in my opinion at least.
1/4th the pressure is still problematic, because what do you do while you're accelerating up to speed? You'd have to use pressurized onboard gas to levitate with, which would then require more vacuum pumping with every run. The Alpha design uses wheels for "taxiing" at low speeds; it's unclear at what speed the compressor is able to provide all of the needed lift.
Relevant because the problem is the frequency, not the amplitude. Large earthquakes tend to cause much lower-frequency deflections, which are far easier to deal with, even if the amplitude is higher. The problem I described has to do with the static height profile of the tube, not the effect of the passing capsule distorting it (which is negligible). Even if the skis (on springs) can accelerate at 10g's to maintain contact with the tube surface, then a 5cm oscillation with 30m wavelength is sufficient to cause the skis to completely lift off the surface of the tube after each pylon, causing a very jarring ride. A low-frequency earthquake deflection on the other hand, say with 200m wavelength, could not realistically have high enough amplitude to cause the skis to skip like this. Of course, if you have the bad luck to be riding the hyperloop straight over the epicenter when the earthquake lets loose, then there will be high-amplitude earthquake waves of all frequencies and all bets are off.
The Alpha proposal calls for a "mechanical braking system"; I agree that magnetic brakes would be preferable in principle, though at Hyperloop speeds there's enough kinetic energy involved that the capsule component of the brakes would likely melt from the induced current. Permanent magnets on the capsule would probably be too heavy. And magnets/electromagnets on 350 linear miles of tube would likely be too costly/complicated. So unless there's a way to have the electromagnet component on the capsule, but make sure that nearly all the heat is dissipated in the steel tube and not the capsule, I'm not sure it would be workable. I have similar concerns about the aluminum capsule rotor, and whether it might become problematically hot during the linear acceleration/deceleration phase. A solid aluminum rotor could absorb the electromagnetically induced waste heat from 0-700mph acceleration without melting (by a factor of about 2), but the Alpha design calls for it to be hollow. And accelerating to 1500mph involves >4x the energy of 700mph
Weeks of coding saves hours of planning.
Actually, high speed rail can climb much better than regular trains.
Why? Both types should be limited to the friction between the driving wheels and the tracks. You can put a motor in every carriage, but regular trains often have that as well. Where is the advantage for high speed rail?
Finally! A year of moderation! Ready for 2019?
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Sure, because the cost of materials has little to do with the cost of building a highspeed railway. You've got a mighty wide right of way, and you need to buy a huge amount of land for that, plus there's a ton of labour to prepare that right of way, clearing it of all obstacles, leveling the terrain, installing the track, the filler, etc.
Well, I don't know about the USA, but in the UK there is no way that you could put a tube on stilts above some-one's land (let alone buildings) without buying it off them, or paying a significant rental for the wayleave, as it is called. Even the latter would only be acceptable if the land use was not residential.
Again in the UK, when railways were first built, in cities a lot of them were built on arched viaducts (in South London particularly) so that the arches could be rented as workshops and warehouses. Or the railways were built underground. The same thing with motorways 100 years later, but even so houses under motorway viaducts generally have to be bought and demolished (not least because such houses would be unsellable otherwise). These approaches are so expensive however that as soon as railways or motorways get clear of the city they get back to ground level. That is even in the cramped UK; I thought that OTOH, except in cities, the USA was wide open spaces. Why put a tube on stilts above a desert or wilderness, unless over a gully?
zblockquote>See: Cabin_Pressurization [wikipedia.org]
A person needs at least 20kPa *from the mask to breathe*. Not 20kPa *ambient pressure*. Please learn to read.
Aerodynamic loading = pressure. If you have high loadings, you have high pressures. Period.
You know when it's okay to shout fire in a crowded theatre? When it's on fire.
'the Hyperloop is a High Speed Railway"
Nope. Rail is heavy and thus mostly must reside on the ground
There are things called viaducts and tunnels. A lot of modern high speed lines are built with one or the other. Japan's in particular are largely elevated, and much of the UK Channel Tunnel link line through south east England is in tunnel. And if the railway (sorry "non-railway Hyperloop" if you picky about semantics) is not "heavy" it will not be carrying many people, an equivalent to Concorde in the airline world; as such it won't be solving many people's transport problems.
and thus cuts everything in half along its path
There are things called bridges.
Look, you Amercans seem to make very heavy weather of railways "cutting things in half". It seems that for historical reasons, when a railway was built in the USA, the upper classes all settled on one side of the tracks and the lower classes and industry on the other. So the town grew up "cut in half", joined by multiple level crossings which are forever a source of frustration and delay. I have a picture in my mind of the train rolling through a city on a dead-straight track at ground level at the end of "Back to the Future Part III" - such a scene is essentially American and I cannot think of a layout like that in the UK. In Europe railways fit in much more comfortably. In the UK you are practically unaware of the existence of railways (many people are) unless you use them. Even farm tracks have their own private bridges or underpasses. In the centre of Birmingham for example you can be totally unaware that there is the biggest station UK outside London beneath and around you, and most of it is not even underground.
and hampers if not stops any traffic along its path.
Along its path ?? I don't get it.
High speed railway .... requires massive earthworks because of the very limited turning radius and limited climb angle of high speed trains.
Obviously you don't know much about railways or dynamics. High speed trains can take much steeper gradiants than lower speed ones, partly because they are so powerful (have to be, for the speed) and partly because their momentum takes them up with little effect on speed (kinetic energy relates to the speed squared). The new lines built for the French TVGs have such gradients, following the natural land contours, that some passengers complain of the up-and-down feeling - like you get with hump bridges on the road. Curve radii are also less of an issue as high speed trains generally tilt into the curve.
A Hyperloop train doing 800mph is going to be very restricted in its vertical and lateral curvatures to limit the centrifugal accelerations (despite tilt) given to the passengers, if they are not going to barf up their last meals.
It requires very specialised rails that have to be laid under very high tension and welded so that the result is seamless and can withstand large temperature variations.
You have just described standard track-laying practice these days. It is not special. Keep up.
It's also much more expensive to ballast because normal ballast doesn't cusion things well above certain speeds and turns into nasty pebbles instead of spikey lumps of rock.
Most high speed track is slab track these days. The effect you describe occurs with track movement and does not occur if the track is properly laid, properly drained, and has modern stock running on it. It is actually more likely to occur on secondary lines with clapped-out rolling stock running on it. Believe me, I am an ex-railway engineer and have had to deal with such trouble-spots on the track .
Whether or not the hyperloop claims are valid, I don't know,
The low costs are fantasy.
What he means is that even though it's a prototype he's still going to charge passengers to ride it.
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Obviously, it would suck if you only had the one train, but what if it worked like a highway and trains could get on and off? So you could have multiple trains sharing the same track.
And, yes, I know, people think it wouldn't be in vacuum anymore, but pumping out air could simply be an intermediate step after people are already on the train, like waiting on a runway for a plane to actually take off.
The ground-preparation benefits of raised roadways have been known for decades, nothing special there. The problems are (1) making a system that interfaces smoothly with ground-level transportation, and (2) minimizing the amount of construction necessary for the spans. The Russians(?) even did some interesting work way back on a system of paired concrete-encased cables that tireless cars could drive along - far cheaper than roadways per mile, and wonderfully suited to rough terrain. But who wants to drive along such a contraption?
You're thinking build-in-place costs, which is always much higher. You would build both pylons and tubes in factories designed specifically to build such things - lengths of double-sided spiral-weld, pressure-tested, heavily lined pipe are already available in suitable diameters and arbitrary lengths for urban waterworks. It's just a matter of dropping them in to place with sufficiently flexible airtight strain relief joints and throwing in an occasional vacuum pump to compensate for the inevitable leaks. Make the proper pylon-riding transportation and deployment rigs and you could be dropping them into place at an astounding rate without having to deal with ground-level delays.
As for transportation energy - that's part of the beauty: any point where you want serious acceleration in one direction, you also want serious deceleration in the other, and thanks to the external linear motors in use you can recycle all that energy (minus inefficiencies), using the energy generate by slowing one car to accelerate the one going the opposite direction.
As for what happens when a major leak develops - well that entire leg of that tubeline, whatever's between the closest isolation valves (the nearest two stations if nothing else) will have all the cars rapidly slow down as air pressure in the tube climbs, eventually coming to a rest on their wheels. Then, ideally, all the cars fire up their back-up motors and trundle down to the next station where they can get back into a properly depressurized line (separate "tug cars" are another option, but have multiple issues) It's a major inconvenience for passengers, but not nearly so bad as a failed railway - the route still works, it just gets suddenly slow until the leak is fixed.
As for the "failure" of rail in the US, perhaps you're not aware but there are essentially *no* major passenger rail lines in the US - it's all owned by cargo-moving companies, and passenger trains just rent access in between the cargo trains. And if you've spent much time riding Amtrack, you know they *suck* - the line is always pretty much the same, but they are chronically incapable of keeping a schedule, and any time there's a rail conflict *they* are the ones who have to sit interminably on the sidelines while the cargo trains that actually know how to keep to a schedule pass.
Plus there's the "minor" issue that virtually all the rail systems in the US are *old*, and can't support high-speed trains - so you're dealing with trains that aren't notably faster than your car, even at the top speeds they rarely reach. And then there's commuter lines which, for the most part, are an even greater embarrassment. Hyperloop on the other hand could be considerably faster than airlines for short-to-medium hops (long hops too, but that's getting ambitious) for potentially cheaper than rail, and the functioning of the system would rely on it being almost fully automated, so no idiots at the helm screwing things up for everyone with their inability to keep to a schedule. Plus no issues with weather. I suspect there would actually be quite a demand.
There might be issues to be discovered, but then that's why they're making a test track, now isn't it?
--- Most topics have many sides worth arguing, allow me to take one opposite you.
The mask pressure must match the ambient pressure, or else the wearer's lungs will rupture (unless they're wearing an enclosed pressure suit). Please learn physics. Again, this is the reason for the 40,000ft flight ceiling for commercial aircraft; oxygen masks rapidly lose their effectiveness with an ambient pressure below 0.2atm, which is why pressure suits are required for pilots flying at higher altitudes. The absolute physical limit for unpressurized flight is known as the Armstrong Limit, which occurs at about 62,000 ft; even wearing an oxygen mask, your bodily fluids will start to boil above that altitude.
The high loadings are from high _variations_ in pressure. The average pressure around the capsule is still equal to the ambient pressure. Leaks in the passenger compartment are almost certainly side-facing, so the capsule will equalize to the pressure of the air on the sides of the capsule (which will be close to ambient or likely below, due to the Bernoulli principle), not the higher pressure in front. And note that the variations in pressure don't have to be very high to cause serious buffeting. The Hyperloop capsule masses 15000kg, with a frontal cross-section of about 2 m^2. Applying an extra 1atm to the front of the capsule will decelerate it faster than 1g. If the air beneath the capsule transiently becomes about 0.03atm higher density than the air above (due to turbulence or ground effect), it will lift the entire capsule off the track. This is the worrisome high-speed aerodynamics I was talking about.
Weeks of coding saves hours of planning.
Analyzed in detail. Because everybody knows that every major construction project is completely in budget and prepared for every contingency.
I like you Rei, I really do - I've ready your posts here frequently enough to conclude that you've got a first-rate brain behind that keyboard. But I think we've found your blind spot - Hyperloop is an exercise in fatuous navel gazing. If it was as easy / revolutionary / sure-winner as Elon proclaims, he would have undertaken those long before taking on the automotive industry and the privatization of space travel. Neither of those are particularly "trivial" undertakings -- and he chose those over Hyperloop for a reason.
Everything I mentioned is covered in the Alpha proposal - with much hand-waving and assumptions that "somehow all this stuff will fall into place." Assuming that these rough and ridiculously optimistic estimates are in any way reflective of the actual reality is foolish. The Alpha document is VERY thin on technical detail, and assumes that pretty much all the components needed are available already and can be bought off the shelf and snapped together to build the Hyperloop.
The cost and operation of this system will be, if built as described, several orders of magnitude more than projected in that alpha document.
All good points -- I have no idea if the skis would be able to handle these angles or not. If one part of the ski is able to handle higher pressure and pass the load to the other side of the ski, I don't see why it wouldn't be able to handle even a horizontal alignment (with a robust anchoring to the pod, of course). But in this scenario, I believe the entire ski would be below the equator of the tube and still allow for the 1.34m clearance between skis.
As for vacuum forces -- there is no reason that there can't be an expanding cylindrical pressure vessel that contains the two tubes for the length that is needed. So not insurmountable - but expensive.
High-speed rail requires a 100-foot wide right of way for double tracks. It's not just about building over things, it's about not requiring the very wide right-of-way that high-speed rail requires.
http://patft.uspto.gov/netacgi/nph-Parser?patentnumber=5433155
Really, this was patented in 1995
Both are vaporware from the twisted minds of the GOP.