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Hyperloop One Becomes ‘Virgin Hyperloop One’ (techcrunch.com)
364 points by mpweiher 8 months ago | hide | past | web | favorite | 503 comments

Maglev in a tube is a proven technology at full train scale. Here's the Chuo Maglev from the inside.[1] 500KPH in tunnels. They're not pumping down the tunnels, just plowing through on sheer power and money.

The Chuo Maglev makes the Hyperloop One look like a toy project. Watch the video. They have a production-quality train, with tourists and whiny kids riding it, going 500km/h. They've hit 603km/h in tests, but don't run it that hard normally. This is the first section of track between Tokyo and Osaka via Nagoya. Planned opening to Nagoya is 2027. Japan's Alps are in the way. They're tunneling straight through. Longest tunnel segment is 25km and it's being drilled now. 90% of the Tokyo-Nagoya segment will be in tunnel. Stations in Tokyo and Nagoya are under construction. The line will probably run 3-4 trains an hour each way, like the existing Shinkansen.

Hyperloop potentially has a higher speed to 900-1200km/h, but that may not be achieved in practice. The Chuo Shinkansen has a turn radius of 8km, and passengers don't have to be strapped in. Hyperloop would need 4x the radius to go twice as fast with the same ride quality. Laying out a route with a 24km turn radius severely limits where track can go.

Strapping everybody in and pulling 0.5G sustained is not going to go over with customers. Commercial aircraft usually stay within +-0.25G. Maybe 0.5G in mild turbulence, and customers don't like it.

[1] https://www.youtube.com/watch?v=HZ6dYhHIol8

I’d separate:

- longitudinal, predictable acceleration, where you can safely tell people to stay in their seats and all will be fine, I’m quite confident most humans would be comfortable with 1G horizontal that adds up to 1.5G diagonal: that’s basically a roller-coaster; it’s not too bad if you ease people into it, i.e. you minimise the jerk;

- lateral, predictable acceleration, like one would expect in turns: not familiar with train technology enough to know if you could adapt pendular train to MagLev, but it seems like a simple enough hack to increase comfort significantly;

- vibrations and turbulences: seem unlikely in a tube on rails, without a train coming in the opposite direction. Those definitely, customers don’t like.

Lateral acceleration is much more annoying to deal with than longitudinal or vertical, even if it's constant. Perhaps they could tilt in bends to convert some of that lateral to vertical?

Yes, and with no windows, there's zero correlation between acceleration and visual cues. That's a perfect recipe for motion sickness.

Our local trains have cars that can lean a bit on their own. Bank the track a bit, lean the car as needed, the humans on board don't recognize a turn unless they're watching intently out the window.

Banked corners are a thing. The problem is that when you have delays and vehicles operating at low speeds the track is still banked

Hence tilting - high speed vehicles tilt, low speed vehicles don't, and everything works out ok.

Amen. If you want a fast train in 2017, hire the people who have been winning in that department since 1964.

Also, the リニア will cut travel time between Tokyo and Nagoya from about 100 minutes to 40 minutes, which is a big difference for people who do business between those two regions.

That's insane. If you didn't have to switch trains for Philly (30th St) to NYC, an avg ride could take a bit than 100 min if there are only around 7 stops the entire way (normal stops would make the ride like 2 hours). Reducing those numbers by more than half would be incredible. Even if this is just a pipe dream and there isn't a direct train between the two cities right now anyway.

Stops and waiting are by far the biggest slowdown in train travel. In a moderately dense area, if you could magically put enough trains on the tracks to offer all important connections as high frequency point to point connections, you would get enormous improvements in travel time even at moderate cruise speed. Tracks are empty almost all the time because trains cannot evade and have very low deceleration, they have to reliably coordinate far beyond visual range. And by reliably I mean more than aviation grade reliability, because there would be no redundancy and no Hudson River to splash into when you mess up that part.

The good news is that it's "just" an information problem (well, so is landing a rocket, in a way), the bad news is that the number of possible endpoint pairs in a network is bloody high.

In the end you get back to the old vision of on demand "pods". I suppose that those could still be made "rail-efficient" if you make them robotically jack into a paceline behind a tender that provides drafting and power grabbed from an overhead line (you would not want this per pod), but run on battery power only to get to/from the tender at endpoints (which the tender and its followers passes non-stop) and when the paceline gets broken by someone exiting. If you can start over on a new right of way, this is what you should do (in a pinch, you could also take over the leftmost lane of existing roads, but that's not a good place for doing construction and maintenance).

I think you can get most of the benefits just from a well designed timetable. I get the impression that's mostly how they make it work so well in Japan.

There tend to be at least local and express services on almost all routes, and often multiple tiers of express. Another common pattern I've seen is having several commuter services which each run stopping for a different section of the route, and then run express to the central stations. This gives passengers the benefits of swapping between local and express services, without them loosing time changing trains.

Of course, all of this is a lot easier when you already have the passenger numbers to support it.

NJ transit does do the minimum of express for the farther out places from NYC. Nothing as in-depth as you're explaining. But as you said. The numbers wouldn't support making things too much more complex. That's why my original post mentioned a limit or 7 stops between philly and NYC as an example of a semi-express train. Though a hypothetical express train would probably actually be 5 stops max.

I think straight line distance of NYC -> DC is a little further than Tokyo -> Nagoya, but even the current Nozomi Express Shinkansen would be a huge improvement over Amtrak.

Oh wow didn't realize the distance.

Its absolutely nuts. With all the housing pricing problems we have in the US its crazy to me that we don't have HSR popping up everywhere to ease restrictions on commute.

Highways are paid for w/taxes. Rail gets no subsidy. Sad really.

Turn radius is mostly a cost question. If you want to get from city A to city B the most direct path has zero turns. It's also got stuff you want to avoid to save money.

Hmm, I hadn't thought of the Chuo Shinkansen as "Maglev in a tube" before...

This makes me wonder, if hyperloop research develops reliable vacuum tubing, whether they could encase the overground sections of the Chuo Shinkansen to make it even faster...

The biggest problem people have with Hyperloop is because it certainly seems like Elon Musk just waltzed into the high speed rail debate and Dunning-Krugered some crazy scheme that doesn't look anything at all like conventional approaches to the problem and thus doesn't jive with any common sense we might have built up around different transport methods.

But that's kind of what Elon Musk does: he Dunning-Krugers himself into a new industry every couple of years, using a simplified, undergraduate physics level of analysis to find something that (to an optimistic non-field-expert) looks like a better solution to the problem.

And the most annoying thing of all is that he usually succeeds. Often in spite of his original idea being technically wrong. For instance, Falcon 9 was supposed to be recovered with parachutes... that didn't work, and people who were working on vertical landing rockets told them that, but at the time Elon just rolled his eyes and said "just use parachutes." But SpaceX/Elon found out the idea didn't work and switched to the "correct" solution and got it to work operationally (and with paying customers) much faster than people who had been working on the problem for years before.

The moral of the story is that it's often better to be able to execute fast even if you start out wrong than to take your time with the right answer.

That's a rather cynical view of what is essentially him doing dimensional analysis to find out if it's worth putting effort and money into these ventures, and then hiring a bunch of really good engineers to go towards it.

Agreed. I'm a physicist, so feel the same way, but people who are actually experts in whatever field usually hate that... https://xkcd.com/793/ "Liberal arts majors may be annoying sometimes, but there's nothing more obnoxious than a physicist first encountering a new subject."

> Elon Musk just waltzed into the high speed rail debate and Dunning-Krugered some crazy scheme

I think it's incredibly important to segregate Musk's work, i.e. SpaceX and Tesla, from his proposals, e.g. the Hyperloop, modular infrastructure and other things.

Nah, the Dunning-Kruger thing applies equally well to Tesla and SpaceX. He had no experience in either field before starting those companies. It's just that he has, in spite of all probability, succeeded and so you see them in a different light.

Didn't he actually design the first rocket himself? He's quite smart. I don't think "industry experience" counts for much. By the way you're using "Dunning-Kruger," it's unclear that you actually know what it means...

I think GP could have a point with Dunning-Kruger applying to EM. Here's the main difference IMO: By far most people who experience the Dunning-Kruger effect have no way of self correcting, i.e. they don't recognise when they're wrong or they do when it's too late or they keep on their path nevertheless because of the sunken cost fallacy or vanity. EM on the other hand has proven to be very good at admitting and correcting his mistakes. That filter effect combined with simple uniform-density-spherical-cow type modelling for his initial guesses combined with some of the best computer simulation experts in the world seems to be enough to have catapulted his endeavours to orbit and back - both figuratively and literally.

I just Dunning-Krugered myself about Dunning-Kruger.

DKE = lowest skilled people think they are a little above average. Low skilled people do not think they are as good or better as a very high skilled individual would be.

Look at the graphs in the actual study:


It's more like the range of 10-90% actual skill is simply transformed to 50-80% perceived skill. The absolute ranking of person by skill order is still accurate.

If Elon Musk is actually at about the 75% percentile of skill which maybe he is, if you turn the graphs that DK reported into a function of actual to perceived skill, if you fed 75% into that you would get like maybe 73%. The real vs. perceived skill curves cross at about 70%.

Versus the popular supposed version of DK, being something like "you are wrong and you do not know it." It's easy to describe the DK to sound like it's a profound explanation of that, but if you look at the data they reported, it's a much more timid effect than it sounds like it is.

To put it another way, low skilled people think they are better than most of the other low skilled people, but they themselves do not perceive themselves to be better than someone who does in fact know what they are doing. Low skill people would think they are a bit above average, not a superconfident expert.

>I just Dunning-Krugered myself about Dunning-Kruger.

Ultimately you didn't. That very comment shows you were able to recognize and correct for your mistake in the end.

Perhaps if you insist you've Dunning-Krugered yourself about Dunning-Kruger, then I may agree that you have in fact Dunning-Krugered yourself about Dunning-Kruger.

It's turtles all the way down.

He did do much of the design on the first rocket, which is probably why it blew up 3 times. He was smart and dedicated enough to figure it out eventually, but he totally stumbled into the field completely clueless.

i would very much doubt that. i remember reading an article early on about some russian investors or engineers noting he knew almost nothing and that he was just reading a lot of university textbooks on areospace engineering.

> Didn't he actually design the first rocket himself?

I'm pretty sure there were core employees (not Musk) working on every part of the rocket from the beginning. This is documented in the Vance biography, IIRC.

I think having no experience is an advantage in industries which have become stagnant. If the industry is stagnant, than in a sense, most people in the industry is a failure. I'd compare this to visual programming. There is a small click of people in visual programming who have been at it for decades. They are failures, as none of their projects or ideas have had any value. Taking advice from them is worse than useless.

Edit: I changed what I wrote, so as to not claim that "everyone" is a failure, some people worling in visual programming are still having fresh ideas. But they don't have the attitude of being "industry insiders" the ones with fresh ideas are the least arogant and offputting to outsiders. They are the ones who are least likely to put someone like Elon down as being inexperienced.

Maybe his experience is in building successful companies.

This is also a good time to introduce the concept of survivorship bias. There's a fair chance that it was mostly luck, not ability, that it ultimately succeeded.

I don’t know there are a lot of people who have crazy ideas and succeed once despite all odds.

Elon Musk did that twice at a very big scale with Tesla and SpaceX. Both companies were supposed to fail and yet the succeeded. And while it is not my generation I believe zip2 and PayPal also had pretty novel concepts which were supposed to fail back then too.

He has just done it too many times to be just luck. Sure there was also a lot of luck, but it takes more then luck to do that with at least two successful companies.

There are far more people who tried crazy ideas and failed, and are promptly forgotten. The whole point of survivorship bias is that you have to be cognizant of the data points that failed and therefore aren't recorded, not just the ones that survived and are recorded.

According to this: https://www.inc.com/leigh-buchanan/us-entrepreneurship-reach... there are 27 million entrepreneurs in the the US. That's a large enough number that even if the chances of each individual entrepreneur having a big hit is just a few percentage points, then there are bound to be many entrepreneur who have multiple successive big hits. Especially considering how many people who are even tangentially related to a successful startup describe themselves a founder or co-founder, resulting in the padding of the success rate.

My point being is that we can't rule out the possibility of it all being luck or mostly being luck. Sure, it legitimately could be skill, but there is no way to know for sure, at least currently.

> "all being luck or mostly being luck"

Seriously? What, he flipped a coin a million times which determined what he's going to do next? How are you defining "luck"?

Not the OP, but the point of survivor bias is that there were 10 million people flipping coins for the first "moonshot" idea, and let's say 1000 succeeded; then those tossed the coin for the second moonshot and only 1 succeeded. Was the one who succeeded so much better than the other 1000, or mostly luckier?

But my point is that he didn't flip thousands of coins. He made thousands of calculated decisions. His thousands of decisions resulted in success. Others, with their own thousands of decisions did not. I don't see the "luck" here.

The point is, if enough of people are making decisions, success is not sufficient to distinguish a "calculated decision" from a lucky one.

I get the point, but it's ridiculous. It's like monkeys on a typewriter coming up with Shakespeare. Sure, it's theoretically possible, but the odds are incomprehensibly small based on luck alone. If a monkey did write that prose, it's probably a pretty special monkey. Likewise, Elon is a pretty special monkey too.

He took thousands of calculated risks. Lots of those calculated risks didn't pay off, you can be sure. But enough of them did. There are no Übermenschen.

I'm not saying he's the greatest person of all time, or even the smartest, but he's demonstrably one of the best at getting very large high risk projects off the ground and building tons of support for them. That's not luck.

Impress me once, you lucky. Impress me twice, I'll have to talk about survivorship bias.

Impress me four times, and I'll start misquoting Napoleon: "If he's been lucky that often, he's the General I want for this"

I used to think that about Musk, but his successes seem to be piling up. Specifically: Paypal, Tesla, and Space-X all seem to be rather successful.

SolarCity failed (and he had to buy it back himself with Tesla), Paypal was a success but it wasn't his, his part was x.com which was kind of a failure on its goal and had to sell (just because it sold for a lot of money doesn't mean it succeeded, in the terms of "success" we're discussing in this thread).

Tesla has yet to make any money and fails to meet its deadline, and it's yet to see how it will far now that the car giants are turning to EV (especially with many countries setting deadline in 2016 and 2017 about the end of non EV cars, which jolted all the big ones into joining).

Space-X is for me his one real success so far, it leaned on a lot of public funding to do it so it's really not the kind of things usual for HN, but they said they would re-use when everyone else said "can't be done" or "not worth it", and they're getting there.

Wouldn't be so sure about Tesla since it has yet to turn in a meaningful profit. SpaceX is a maybe since we don't know its internal finances. We're also ignoring SolarCity, which by any metric was a failure.

In case anybody else was not familiar with David Dunning and Justin Kruger:

"The Dunning–Kruger effect is a cognitive bias wherein people of low ability suffer from illusory superiority, mistakenly assessing their cognitive ability as greater than it is."[0]

[0]: https://en.wikipedia.org/wiki/Dunning–Kruger_effect

..and it's quite the charge to throw at the guy with the first commercial spacecraft and the leading electrical vehicle.

The moral might be that hubris along with billions in cash can accomplish the things the person with hubris set out to do.

Elon Musk didn't start out with billions of dollars, and he has almost no liquid assets (he borrows against his stock when he needs cash).

But this is a good point. Lots of talented people have good ideas that end up going nowhere because of lack of capital for implementation.

He spent all his money on his trio of companies by 2008. He could've relatively speaking for people worth a hundred million to billions, be worth very little today.

I don't think he has ever in his life had a billion in liquid assets. You could argue I guess, but he likely wants to keep a majority stake in SpaceX, and likely doesn't want to go below 20% stake in Tesla.

The viability of Hyperloop One should not be the focus in the context of this article. That's not what this is about at all.

It's that Hyperloop One needed Richard Branson on board because Elon Musk is creating his own competitor now. This is an incredibly smart move to ensure the survivability of the business from a publicity perspective.

Branson has a history of doing things that people thought impossible or just a bad decision (like creating an airline company). Public perception is the name of the game at this stage, not just feasibility. From that perspective, Hyperloop One has effectively done one of the only strategic moves remaining at this point that ensures it has any chance of persuading a government to select them as a preferred vendor (or continue doing so).

Branson's missing a d from his almost nominatively-determining name — the guy's got a talent for self publicity over challenging the incumbency, which for the most part he hasn't since launching Virgin Airlines and Megastores, which were both back in the 80s.

Downvotes? Presumably not from Britons or anyone who knows anything about the guys history?

So what HAS he done then, other than brand anything he can then offload to third and fourth parties to run the businesses for him?

And don't say Virgin Galactic - that's just some clever peripheral branding to encourage the likes of the downvoters here that he is in any way novel or dynamic.

He's marketing clever, not strategically or developmentally-so.

Well, you're criticizing him for only acquiring things and slapping his brand on them. But the criticism is leveled in the context of him investing in an unproven technology. It seems like your comment would be more apt if he were taking an action that follows the pattern you are criticizing. For example, if he were acquiring a computer company and calling it Virgin Computing or something.

That's fair enough, I suppose. I guess I simply distrust his motivations beyond self-aggrandizement and inflating the idea that he's somehow an ideas man, when I can't for the life of me think of anything novel he's done for literally decades.

I'm coming across like a 'crab in a bucket' here - I've nothing against the guy or his success, but I'm not for one second convinced he's 'challenging the impossible'.

He's worth $5 billion. He's a high-school drop-out dyslexic that started from nothing. He built a successful airline and record label, along with countless successful branded companies whose success partially rides on the vast effort he has put into building his own well-known brand - a substantial feat unto itself.

Yes, golly gee, what HAS he done.

I trust my respone to 'waegawegawe' pads out where I'm coming from.

He has a certain reputation here in Britain, however we here in Britain also have a certain reputation of shitting on people's success - I sincerely hope that's not how I'm coming across here.

Anyway, this is tangential nonsense, I'm sorry for diluting discourse!

> however we here in Britain also have a certain reputation of shitting on people's success

That's okay, I appreciate you loaning us John Oliver. ;)

In a sense, I think you gave him to us. You often do :)

While what he has done should be commended, I don't think it's fair to say that he "started from nothing". His own mother was an entrepreneur, obviously not as successful as him but come on, he went to a "prep school" for goodness sake[1].

1 - https://en.wikipedia.org/wiki/Richard_Branson#Early_life

The point is that he built his businesses from scratch, and did so with a significant learning disability that meant he struggled to understand even basic P&L statements and balance sheets. His mother didn't build his record store or record label. His mother didn't build his airline. His mother didn't build his brand.

His early business successes were built from nothing. They weren't seeded with millions of dollars. They weren't inherited. He rolled one success into another.

This obnoxious notion, so common on HN, that someone has to crawl out of a ditch with not a penny to their name, or they're not self-made or deserving of any credit for their own success, needs to stop. It eliminates nearly every possible success story that could exist (which is of course the whole point). It's nothing more than a base envious desire to drag someone down because they've been successful.

On the other end is the absurd notion that someone who starts with a (comparatively) huge cushion or even more is "self-made" in any meaningful sense of the term.

Take this example: Bill Gates as compared with Jan Koum. Applying the label "self-made" to both of them is nonsense. There's nothing "envious" in pointing out that one had a lot more going for him than the other.

I don't know much about that, but ever since the 'Traingate'[1] spectacle I've lost all respect for Branson.

1 - https://www.youtube.com/watch?v=47fqjA8CwGE

For me the sheen came off his lustre a bit back when I was trading at festivals, and at his 'V' festival the only cola drink that was allowed to be sold on-site was the God-awful 'Virgin Cola'.

Minded me of the sort of criticisms he'd level at the likes of BA back in days of yore...

There was never any lustre for me, the first thing I ever knew about "Virgin" was "virgin mobil, which was "free" if you'd click through ads. It was aimed at youth who didn't have much pocket money and I thought that was just awful that teens were clicking through ads to answer the phone.

"Branson's missing a d from his almost nominatively-determining name"


Edit: This has been a fun puzzle. I read the Wikipedia article for "Nominative determinism" and I've been swapping the letter "d" into various positions of his first and last name trying to figure it out. No luck yet!

I was thinking "Richard" - "d" = "Richar" or "richer"

I also was confused, but they probably mean “Brandson”

Yes, there we go. I'm genuinely surprised it was anything other than fairly obvious. Perhaps his reputation's different away from the UK?


I'm massively wary about posting chat here (with fairly good reason) but thanks.

There should be an allowance for balance and humanity in HN comments. Not everything need be ultra-violet literal on the spectrum!


Seems more like a brand-father, though.

he hasn't since launching Virgin Airlines and Megastores, which were both back in the 80s.

There's a jar of Branson Pickle in every home in England!

But his moves into healthcare are looking extremely dodgy and of course he lives offshore in a tax haven.

> There's a jar of Branson Pickle in every home in England!

Is this humour? The pickle, and beans, are Branston.


> But his moves into healthcare are looking extremely dodgy

His healthcare stuff is really dodgy. There are already serious concerns about care and treatment at his places.

Branson owns both an airline and a high-speed rail service. He seems like an eminently sensible choice of partner for Hyperloop. The institutional expertise that Virgin Group are bringing to the table will be at least as important as the capital investment.

> Branson owns both an airline and a high-speed rail service.

I can't speak to the airline but the rail service is universally reknowned in the UK as "piss poor", especially since they get huge government subsidies.

Both Virgin Trains (51% Virgin Group) and Virgin Trains East Coast (10% Virgin Group) pay large net premiums to the government (£153 million and £204 million respectively).

The huge government subsidies go to Network Rail, a company wholly owned by HM Government, and are never seen by any of the train operating companies (except insofar as they are indirectly subsidised given they don't pay the full cost of maintaining and improving the infrastructure).


Has a total net of -£225M from Virgin in 2013/4.

This shows them as still being net-subsidised: http://orr.gov.uk/__data/assets/pdf_file/0008/25757/rail-fin...

Both of those are including the Network Grant; note the ORR document gives Virgin Trains East Coast as paying a net premium in 2016–7 (which I hadn't been able to find figures for before) even including the Network Grant.

Note that apportioning the Network Grant based on percentage of track access charges isn't entirely fair: Virgin Trains notably pays above average per km as a result of funding agreements for the WCML Modernisation programme in the 90s/00s, and as such given the different funding agreements for different network improvements (with the shortfall mostly coming from the Network Grant since the demise of Railtrack plc) it doesn't really make sense to apportion the Network Grant in that way.

The problem is it's a separate organization spending the money. So, while you can point to cost aka actual spending it's unclear what the net benefit from that spending is.

> Both of those are including the Network Grant

The result is that Virgin (as a whole) gets more from UKGOV than it sends back as shown in UKGOV's own figures.

> isn't entirely fair

You want to argue with UKGOV and their own numbers, go ahead, but it doesn't change what they currently are.

Are you kidding? The Virgin carriages are insanely nicer than all the other ones; they feel like airline cabins, while other carriages feel like buses.

Having used Virgin West Coast many times since they took over, sure, they are better than some. When they're not reeking of urine because the toilets have leaked -again-. Or when the aircon isn't broken. Or when the heating isn't broken. Or when the toilets actually work. Or when you can actually use a carriage because they aren't 200% overbooked due to Virgin's utterly insane customer hostile "peak" restrictions and the ridiculous waste of space by empty first class carriages.

The viability of hyperloop is nil. It doesn't exist. It is literally physically impossible for it to be viable.

I think it's on-topic whenever hyperloop is on-topic.

Physically impossible or economically impossible? The physics doesn't look impossible at first glance.

Okay, great. It's on topic. So what?

Why is hyperloop's viability nil and nonexistent?

That's been well covered elsewhere in this thread and other threads.

I'm not going to say the claim it's not viable is original, nor am I going to argue that claim. But it is on topic.

Something I wrote a while ago.... w/ back of the napkin calculations.......

Why I wouldn’t invest a money into Hyperloop

- Stabilizing a single fault line risk pylon is more than $250K.

- How many million are needed for vacuum pumps to evacuate 100+ million cubic feet of of pipe to 100 Pa?

- Hot air discharge needs to go somewhere. For every 1 bar pressure, you need ~200 to ~400 cubic meters of volume which is larger

- This seems very much like one of those Andy Grove Fallacies.

- The hyperloop is a mega engineering project on the ground. Nobody on their team is a civil engineer. Looking at their team objectively, there seems to be a mismatch of competency.

- At its core, the science i good, the cost-economics do not work. Das ist nicht gute.

I don't think it's right to use figures that can change to disprove an Elon Musk concept. If you did that back in the day, you would say there's no way Tesla could work because the cost of batteries is prohibitive and the supply too limited.

There's a very pertinent historical reference point: Ferdinand de Lesseps. He built the Suez Canal from 1859 to 1869, a task which was considered by many to be impossible or at least impracticable [1]. After achieving resounding success, he then turned to Panama to try building the Panama Canal. In this venture, he turned out to have several very wrong ideas (it's not feasible to build a sea-level canal in Panama), and the French effort failed so hard it actually brought down the French government [2]. He was successful in the first venture but for different reasons than initially assumed (namely, the Suez Canal isn't all that challenging from an engineering perspective; it's just capital-intensive), and his failure in the second venture comes from misunderstanding the problems.

[1] There had been canals in the past that traveled from the Red Sea to the Nile delta, but these invariably silted up rather quickly (the Nile was sediment-heavy, and wind-blown sand is quite common in the region). Thus there was historical evidence favoring the idea that the dredging maintenance fees would exceed the revenue from passing ships.

[2] Of course, this was the Third Republic, which is notorious for having provided series of weak, unstable governments replete with scandals that prompt new governments. Ironically, the Third Republic was the longest-lasting form of government France has had since the Ancien Régime.

To this day, the Third Republic is still the longest lasting.

Yes, but we could see that batteries needed to get X better in order for us to achieve Y results in the future. But how much better do vacuum chamber technologies have to get before you can make the biggest one ever built, that also has a high-speed capsule traveling through it, that is also impervious to armor piercing bullets? Furthermore, imagine if every airplane had to fly the exactly same path, and if any failure on that path prevented (at the very least) all subsequent planes from traveling that path. And finally, how are security lines going to get shorter if the stakes will be at least as high as airplanes?

I don't know the answers to these questions, but what I do know is:

1. Elon Musk has thought about them more than we have.

2. If his initial concept turns out to be incorrect in some way, he will change it until it is workable.

Are airliners impervious to armor piercing bullets? As I understand it, a small bullet penetrating the loop will cause a minor release, not a catastrophic event. It's not correct to hold the Hyperloop idea to standards that we don't apply to other forms of travel.

This is the real insight.

Assuming your are correct and Branson knows it because he hired good engineering advisers. Why would Branson get involved ?

- It is a cool project he wants to be part of and he is willing to pay to see. (I would probably do that)

- The benefit is not to reach the goal but all the technology that will be invented trying to reach the goal.

> Why would Branson get involved ?

Branson is notorious for burning other peoples’ money. Look at Virgin Galactic: it’s New Mexicans’ [1] and Floridians’ [2] tax money plus some duped Emiratis [3]. (They also pre-sold tickets [4].)

[1] https://www.theguardian.com/us-news/2015/oct/04/space-travel...

[2] http://www.airnewstimes.co.uk/space-florida-promises-virgin-...

[3] https://dealbook.nytimes.com/2009/07/28/uaes-aabar-takes-sta...

[4] https://www.smithsonianmag.com/smart-news/

Branson's business model is selling the right to use the Virgin brand to other companies. The article doesn't say he made an investment. It is rather more likely that they paid him.

> The article doesn't say he made an investment.

Actually, from the article:

> Hyperloop One has received a significant investment in Hyperloop One

And from the page linked to in that paragraph:

> Delighted to announce Virgin Group’s investment in Hyperloop One

Not exactly ambiguous.

Is that actually the case? My impression is that the vast majority of companies bearing the Virgin brand was either started by Virgin Group, bought by them, or has seen a significant investment. Many have since been divested again, and continued to license the brand, but I've not heard about any cases where they just licensed the brand without other financial involvement. Maybe I've just not paid attention?

https://en.wikipedia.org/wiki/Virgin_Group#Subsidiaries_and_... shows the majority being 100% owned by the Virgin Group, though notably none of the airlines nor rail operators are.

So basically Trump with more class?

...and fewer bankruptcies.

Although if you believe Private Eye about the state of Virgin's finances (convoluted, shifty, and blistering opaque), this may or may not be true.

When Musk first said that an LA<->SF Hyperloop could be built for 1/8th the cost of the equivalent HSR, I chuckled and then waited for the punchline, which still hasn’t arrived.

It’s a cool idea and I do want to see more prototypes and feasibility studies, but people need to get off the hype train (no pun intended) and be realistic about the cost.

Okay, we'll bookmark this for the future. Amtrak estimated a HSR/"bullet train" from D.C. to Boston would cost ~$151 billion. Since LA to SF will only be two stops, and we can assume Amtrak estimated at least 4 (Philly and NYC) let's bring the number down closer to $100 billion to make it even.

Do we think the Hyperloop costs are more or less than that? 1/8 of a theoretical $100b is $12.5b -- is $12.5billion for Hyperloop unreasonable? I have no opinion on cost personally, and I don't know economics, but this $151 billion from D.C. to Boston was floated by the established US player in rail infrastructure. Anything less than that number is fantastic, right?

You cannot compare D.C to Boston with SF to LAX. The east coast has much denser population so that you need more tunnels. LAX to SF HSR would not cost $151bn. Start and end are expensive but the part in the middle is "relatively" cheap.

Right, for comparison's sake I chopped off $51 billion bucks from the Northeast Corridor projection in the interest of balancing out the two.

Just because I felt like doing some more Google-fu, I found an article in the LA Times[0] that says a California HSR/bullet-train project is going to overshoot it's original budget (and deadline) of $68 billion. There's a lot of info out there about this project, and it's potential overruns, but let's forget all that and just stick to the original planned cost: $68 billion, so, about half of the cost of Amtrak's northeastern bullet. Let's use that number for our comparison.

If we are going to hold Elon to his "we can do it for 1/8th the cost" blurb, then we are giving him like $8.5 billion to use for his SF/LA Hyperloop. Still, that doesn't sound unreasonable, right? He'll get a good deal on tunnel boring with his other company, and fuselage manufacturing can be handled by SpaceX. When it comes to financing, I don't think it's a major issue compared to other infrastructure works out there.

Like I said, though, I'm just going off the top of my head. I don't know finance or economics or vacuums or magnets.

There's a new LIRR train being dug in NYC called East Side Access. This is a commuter rail line, and is going to cost ~$10 billion or so[1]. Logistically these aren't the same, obviously, but if adding to the LIRR is worth ~$10b then surely the Hyperloop experiment is as well, right?

EDIT: Also, just for disclosure, I don't live in California and I'd probably never end up using the Hyperloop myself so I'm neither for nor against it versus any HSR. I just want to entertain the idea that cost shouldn't be the main focus of discussion IMO.


0. http://www.latimes.com/local/california/la-me-bullet-train-c... 1. http://web.mta.info/capital/esa_alt.html

> If we are going to hold Elon to his "we can do it for 1/8th the cost" blurb, then we are giving him like $8.5 billion to use for his SF/LA Hyperloop. Still, that doesn't sound unreasonable, right

I think boring company claimed it can bring down costs to 100 million dollars per mile (how? Just reduce tunnel size! SMH. Plus 100 million dollar a mile isn't too far from prices of current tunnels). Sf to la is 380 miles. That's 38 billion dollars just for the tunnel?

I think hyperloop is certainly feasible, if you spend hundreds of billions in it, the problems can be dealt with costly engineering.

If you think hsr will cost 150 billion, a maglev will be costlier, tunnels are extremely costly to build, but building a maglev in a vacuum tunnel will cost only 6 billion? How will cost savings of an order of magnitude happen?

> Okay, we'll bookmark this for the future. Amtrak estimated a HSR/"bullet train" from D.C. to Boston would cost ~$151 billion. Since LA to SF will only be two stops, and we can assume Amtrak estimated at least 4 (Philly and NYC) let's bring the number down closer to $100 billion to make it even.

You're starting with the wrong number. The $151B number is Amtrak's estimated cost for it's "shoot for the stars" plan. Its basic NEC stretch plan is effectively 4-track corridor (shared with commuter rail) from DC to Boston, with new stations and new inner city track being laid in Philly and Baltimore, two new Hudson River tubes and a new station annex in NYC, among other less notable improvements. I don't recall if the "abandon current Connecticut track and instead go from NYC along Long Island and tunnel under the sound" plan is in that tier or the next one. The stretch tier is somewhere in the region of $70B.

The reach for the stars tier is "do all that, and then build a parallel 2-track dedicated HSR track from DC to Boston." That's $150B. Which means building dedicated track from DC to Boston is only $80B. The estimated full buildout for CAHSR (including San Diego and Sacremento) is around $80B, as I recall.

Meanwhile Switzerland, one of the top most expensive countries in the world, has tunnelled at the base below the alps (one of the most difficult terrains to tunnel due to vertical sediment layers) for ~20B. Workers died on that project too, but that risk is simply being managed rather than grinding everything to a halt.

I'd argue it's absolutely possible to improve the cost on American public transit infrastructure by one to two orders of magnitude if you can simply get a way around government capture.

While American construction costs do seem to run higher than comparative costs in Europe and Asia, the multiplier is closer to something around 2-3×, not 10-100×.

The cost of the Gotthard Base Tunnel comes out to around $300-400 million / km. By comparison, the Second Avenue Subway comes out to around $800-1000 million / km (I'm subtracting a bit because the subway has three stops--which tend to be really expensive money pits--and the base tunnel does not).

How much was there in land take for the Gotthard Base Tunnel? How much land take would there be for Amtrak's $80B line from DC to Boston?

My guess would be that the cost of land in the north-east, combined with AFAIK pretty strong ownership rights, makes it that expensive.

Honestly, 12.5B look like a ridiculously small amount to me for an infrastructure project stretching along 550Km and involving an unproven, technically very challenging technology.

I'm not saying the hyperloop is a good or bad idea, but any suggestion that it would be cheaper than the equivalent HSR seems utterly insane. How could it possibly be cheaper? You have the same ROW requirements, exponentially more expensive track, and the overhead of the fact that it's brand new technology. The fact that the vehicle itself might be cheaper than an HSR train after the tech scales up is almost an afterthought next to those costs.

The track should be cheaper because hyperloop has (almost) no impact on existing infrastructures. Expropriation costs for train are huge.

How could the Hyperloop not require the same expropriations? A giant tube isn't any smaller than a train track. Is it the fact that it's elevated? Rail can be elevated. Yes, rail is heavy, but so are giant evacuated steel tubes.

Run it down the center of the freeway? Having stations for trains in the middle of freeways isn't great for pedestrians, but might be fine for long distance transport such as hyperloop.

HSR is supposed to be log distance transport. It's I meant to solve the exact same problems as Hyperloop, but by powerful engines and streamlined railcars instead of evacuated tubes.

Again, why not put HSR tracks in the same place you'd put a Hyperloop track? Put the station in the same place. The tubes aren't smaller or lighter.

I think he's planning on making lots of tunnels.


Tunnels are very, very expensive.

e.g. https://pedestrianobservations.com/2016/12/15/second-avenue-...

> The total length of the project, from 96th Street and 2nd Avenue to 125th Street and Lexington, is about 2.7 km. At $2.2 billion per km, this sets a new world record for subway construction costs, breaking that of the first phase of the same line, which only cost $1.7 billion per km.

I read one article that blamed the high cost of modern subways primarily on the hyper-elaborate modern subway stations and the actual tunnels are a small component of the cost.

I think you're right - tunnels seem to be about $200-400M per km when considered purely on their own.

Musk seems to think he can do it faster/cheaper. His track record makes it worth considering.

The article I linked to smacks his arrogance down over costs that he's overlooking, but even that may be addressable. Let's see what he delivers in the next 5 years.

> When Musk first said that an LA<->SF Hyperloop could be built for 1/8th the cost of the equivalent HSR, I chuckled and then waited for the punchline, which still hasn’t arrived.

Yeah, and that proposal was for something with much lower throughput, that didn't have stops along the way, and didn't even reach the same areas (they saved money by stopping outside both cities, which the rail line wouldn't do). It also assumed that the tubes could just be placed along the highway meridians (a lot of the money it was supposed to save was from this).

Is this not an attempt to just derail CAHSR, or HSR in general? Nearly every anti-HSR comment is now 'we should build hyperloop instead!'.

That's impressively cynical, but Musk obviously stands to gain a lot if people keep California using roads. California wants to go green and he sells the best technology for green road-based transportation.

I'm not sure it really affects his electronic car business one way or the other. Firstly, he isn't necessarily selling Tesla's to people for commuting between SF and LA, that's well outside his range, and as fast as the supercharging is, it loses out to regular gasoline refilling. Secondly, I'm not sure the amount of people potentially served by the hyperloop is more than a blip in the sales charts for even a regular car company (as deciding factors for car purchasing decisions, it seems relatively low to me).

To be fair, he also stands a lot to gain if Hyperloop becomes a reality.

How does that work? He had an idea and promoted it. No one's going to be paying him royalties for it.

He's also building one, so he has a vested interest in the technology being successful: https://techcrunch.com/2017/08/04/elon-musk-reportedly-plann...


Reminds me of when an actual AI expert pointed out that by making dire predictions about smart AI, that we are nowhere near having, keeps eyes off the autopilot system and the issues with that.

I don't think Musk want hyperloop to be built above the ground. This is just my own personal opinion, not sure if that's how it's going to work, but in one of his interview (TED? I think), he mentioned one of the reasons for his Boring company, was it would be relatively cheaper to build hyperloop - because the atmospheric pressure will be lower underground - and since you don't have to worry about building large infrastructure for only one purpose (hyperloop) - the cost will be much much cheaper. Because under ground tunnels can be build for both hyperloop and roads for cars and it scale better than above ground.

I don't think above ground is economically and technically feasible, there are just too many unanswered issue that almost no one has answer to. Not to mention it will be very very expensive and time consuming.

Tunnel boring is orders of magnitude more expensive than railway construction, at typically ~a few hundred million dollars per mile vs ~a few million dollars per mile. I know Musk has plans to magically make tunnel boring significantly cheaper but you need two orders of magnitude cost reduction to make the tunnel digging not cost more than an entire above ground railway.

Cost references: https://tunneltalk.com/TunnelTECH-Apr2015-Arup-large-diamete...


Why would atmospheric pressure be lower underground?

Everyone has been chuckling about electric cars and private rockets until recently, and that was by experts in the respective fields. Chuckle all you want.

Go here and scroll down to "Select historical production vehicles" - https://en.wikipedia.org/wiki/History_of_the_electric_vehicl...

I grew up in the 70s and saw production electric vehicles that are not on this list. People have been chuckling for a long time and for good reason. It's not that electric vehicles won't eventually be successful -- they must. It's that the time from, "Hey, an electric vehicle would be a good idea" to "Hey, we've figured out all the engineering challenges to make this viable" is longer than the lifetime of most of the companies that entered the fray.

Look at the list of vehicles from before 1990. That's the "getting to the market first" list. All gone. Then look at the list from 1990 to 2010. How many of those will be major players in the electric vehicle market? My point is that I'm relatively old for someone on HN and there have been production electric vehicles since well before I was born. They only started to be viable in the last few years -- and even then, we probably need a few more breakthroughs in battery technology before the market settles out.

Long distance, super fast trains in tunnels? https://en.wikipedia.org/wiki/Ch%C5%AB%C5%8D_Shinkansen I saw the tunnel the other day. I was surprised that practically the whole damn length of the maglev tracks will be in a tunnel, but it makes total sense. That's been under construction for 10 years. They are optimistically expecting to make a profit in 2026 when "costs stabilise".

Will long distance, high speed trains in low pressure tunnels be successful? I have no doubt. Will Hyperloop One be successful? Umm... frozen balls of ice remaining intact in a very hot place probably have a better chance, but I won't say they will definitely fail. If they can secure something like a trillion dollars and invest it wisely over the next 30-40 years, then their chances will improve significantly.

Let me be clear. I was talking about criticism of Musk specifically. Pretty much EVERYONE in the aerospace industry thought he was nuts, and yet SpaceX made it to orbit. Even a couple months before their first stage landing others were saying it was impossible.

Maybe you're looking in the wrong place for the punchline. Perhaps it will be delivered in the final bill for the HSR...

To be fair, if Elon worked in the project for 40 - 80 hours a week, he probably could get a team to accomplish it at 1/8th the cost or lower.

Consider he did this with rockets, getting them to under 1/10th the cost

He hasn’t done that with rockets. He wants to eventually, but he hasn’t yet. Let’s not let hype cloud facts.

He's getting very close, if one is considering domestic rockets. The standard-bearers were the Delta IV and Atlas V, which price out at around $17,000/kg - $20,000/kg to LEO, respectively. The Falcon 9 comes in at about $2,800/kg to LEO.

Comparisons with non-domestic rockets are complicated by state subsidies and differentials in labor costs. But the Falcon 9 is approaching the 10X mark even before reusability has been priced in. Both the Falcon Heavy (in a few months) and the (eventual) reusable pricing should overshoot the 10X mark substantially.

Where are you pulling those numbers from? On ULA's website [1] they say you can launch an Atlas V for less than half the $/kg you listed

[1] I went to rocketbuilder.com and both LEO configurations I tried were around $8,000/kg (and I didn't count the 20% deduction for "ULA added value" since the numbers there are debatable)

ULA has abruptly gotten way more competitive in their pricing. A few years ago they were not. Their "Best deal" for the Atlas V was a 36-rocket "bulk buy" priced the lowest-tier Atlas V 401 at $164M/launch[1]. That does 9,797kg to LEO[2], or $16,740/kg.

The GAO cites $164M/launch as the price for the cheapest Delta V[3] (is there some kind of threshold at $165M?), which when the Falcon 9 was introduced could put 8,500kg to LEO[4], or $19,294/kg. (It has since been uprated and gotten slightly cheaper).

Must've screwed up my calculations earlier, because those aren't tallying. Anyhow, as you can see, SpaceX is already around 7x cheaper compared to where ULA was, and should cross the 10x threshold shortly. Nice to see ULA responding to competitive pressure, however!

1: https://web.archive.org/web/20160324172526/http://www.ulalau...

2: https://en.wikipedia.org/wiki/Atlas_V

3: http://www.gao.gov/products/GAO-17-609

4: https://en.wikipedia.org/wiki/Delta_IV#Delta_IV_Small

For the "block buy", that price includes building the rocket but not the launch.

With rockets he was competing with fat and lazy government contractors for the most part. The hyperloop will be competing with already cutthroat airlines, the goddamn personal automobile, and, ...well, a fat and lazy passenger train company.

IMHO he'll be well over 1/10 the cost before he finishes the thousands of land deals he would need for this, even if he somehow got permission to build it over the highway.

> even if he somehow got permission to build it over the highway.

Hence the boring company.

Which won't do anything, because you can't magically make tunnelling cheap

You can't do it magically, but you can do it by improving the technology - see for example SpaceX.

SpaceX is cheap due to reuse and commercial of the shelf development compared to mostly military-government development.

Tunneling gets cheaper due to <...>? I would be interested.

I guess the Swiss would be interested too.

Musk talked about it here: https://medium.com/@giftedproducts/elon-musks-ted-talk-2017-...

Salient points:

"If you just do two things you can get to approximately an order of magnitude improvement, and then go beyond that. The first thing to do is cut the tunnel diameter by 2 times or more. A single road tunnel has to be 26 to 28 feet in diameter to allow for crashes and emergency vehicles and sufficient ventilation for combustion engine cars.

But if you shrunk it to 12 feet, what we're attempting, which is plenty for a skate to get through, you drop the diameter by a factor of two and the cross-sectional area by a factor of 4. The tunnel costs scales with the cross-sectional area. That's roughly half an order of magnitude improvement right there.

Then, tunneling machines tunnel half time and then stop and the rest of the time is reinforcements for the tunnel walls. If you design the machine to do continuous tunneling and reinforcing, that will give you a factor of two improvement. Combine that, and it's a factor of 8. Also these machines are far from being at their power or thermal limit. I think you can get a factor of two, maybe even four or five on top of that.

There’s a fairly straightforward series of steps to get somewhere in excess of an order of magnitude improvement in cost per mile. Our target actually is that we have pet snail named Gary from....Sponge Bob Square Pants. Gary is capable of going 14 times faster than a tunnel boring machine. We want to beat Gary."

An initial pipeline could be built with a lower target speed. This would postpone some of the potential challenges with regard to heat dissipation, and also route selection.

For example, you wouldn't have to worry so much about tunneling under a mountain to ameliorate the G-forces if you are traveling more slowly. Once you prove out the route (which could still be competitive with any existing train service), you incrementally build tunnels and modify the route to improve your target speed.

(As for heat discharge, Im pretty sure that was addressed in EM's original paper - dumping the excess heat into an on-board water tank which is exchanged at the end of the ride, or are you referring to something else?)

> Das ist nicht gute.

Should be "Das ist nicht gut".

People often, rightfully so, confuse the misappropriated name of Hyperloop One with Elon's Hyperloop idea, his of which I believe does have sound economics and certainly its pro list outweighs Hyperloop One's technology.

Could you point out the differences in both technological and economical approaches?

I'll try to remember to reply to this after the weekend, if not and you're still interested shoot me an email matt@engn.com

All of the Hyperloop development efforts are ignoring the elephant in the room: thermal expansion. If you do the math, the ends of a viable hyperloop track will have to move hundreds of meters [1]. No one has yet advanced even a viable idea for how to deal with that, let alone an actual design. Until that happens, the Hyperloop is vaporware.

[1] It's a trivial calculation. The thermal expansion coefficient of steel is about 10^-5. A typical run of, say, SF->LA is 600 km. Temperatures in the central valley range over about 100 degrees. Multiply everything together and the result is 600 meters.

I dont know if this an elephant in the room. I'm guessing engineers have thought about this and just not discussed it publicly. They have some pretty smart guys.

Also to nitpick, from "the ends of a viable hyperloop track will have to move hundreds of meters" - this doesn't have to be true. There can be absorption points along the track. Overlaps. Or maybe they tunnel the entire way where its cooler. Or wrap the tunnel in something cooling and reflective. We dont have train tracks moving hundreds of meters do we? I dont profess to know the solution, but do know there are solutions somewhere.

Wouldn't they just put accordion joints on the junction at every pylon? It's not like the tube is going to be built as one gigantic piece. It has to be assembled from parts.

The vacuum is the problem. With HSR you also have small gaps in the system to allow for expansion but nothing there requires a perfect surface.

AFAIK, high speed rails do not have gaps. Expansion is controlled by brute force : lots of clamping and massive supports.

They can have expansion joints around bridges, but generally speaking you're correct, they're thermite-welded and adjusted to correctly handle thermal stresses without kinking (heat expansion) or fracturing (cold contraction).

> There can be absorption points along the track

Sure, but these have to hold a vacuum. No one has figured out a way to do that.

I am assured by those in a position to know that thermal expansion joints which hold a near-vacuum are an entirely solved and essentially trivial problem.

I do have some concerns about whether they're a trivial problem within this context. An engineering solution which works in small numbers for PhDs in a lab isn't necessarily scalable to mass low-cost manufacturing, deployed in the field and irregularly serviced by workers of uncertain provenance. But evidently there is a way to do this, at least.

And, more importantly, can be certified for real world use. Considering the speeds used, scrutiny will be extremely high. Even if you use it for freight at first, the track will be close to settlements and any accident could end up in a disaster. The behaviour of trains on tracks is very well understood (learning from accidents), the behaviour of a vacuum train tube is not.

This is a very fair point. There might be components that are routinely used in non-life-safety-critical applications, but this is no guarantee that they will pass certification scrutiny when they are in the critical path for thousands of lives every day.

I worked on an autonomous vehicle project here in the UK about 10 years ago (the Heathrow Pod). The certification process was absolutely intense. And this was for a system that was capped at 25mph; had we gone any faster than the regulatory burden would have become very significantly more onerous (below 25mph it wasn't necessary to test vehicles and infrastructure to destruction; above 25mph, it is).

In this domain, there's a huge difference between a cool engineering testbed, a private pilot project, and running actual service for the public. If Hyperloop is going to be doomed by anything, failure to appreciate this fact is probably at the top of the list.

I work in a lab with vacuum systems that get heated and cooled and we just have segments of flexible bellows like this:


Not sure if the same thing will work at larger scales, but I'm not sure its a fundamental problem.

Wowza, 5" bellow is $450, how cheap could they make 6' one, even in bulk?

Not exactly like that, but yeah, the same sort of idea I'm sure would work.

Gas pipelines hold hundreds of bar of pressure; I don't see how one atmosphere is a problem.

Gas pipelines use Expansion Loops [1] to pick up expansion slack. The problem is that, in order to push people through the tube at 700mph at acceptable G's, you can't put bends like that in the HyperLoop. If you try to send people down a pipeline at 700mph, you would end up with paste at the other side. Gas pipelines are surprisingly un-straight, bendy, and bumpy

[1] https://static.interestingengineering.com/images/import/2017...

Gas has no problem flowing around corners. Gas pipelines are usually not straight lines. Hyperloop will have to be a straight line, unless you want to kill passengers.

Except for the people who invented the accordion and bellows.

Isn't this what a syringe does?

This point is clearly addressed in the paper: The ends of the tube can slide 300 meters next to the station, and the tube is not firmly attached to the pylons but can move to accommodate the expansion.

No. The paper gets this badly wrong. It looks only at the incremental thermal expansion between pylons, and neglects the fact that in a sealed tube the thermal expansion will be cumulative.

"These would absorb the small length changes between pylons due to thermal changes, as well as long form subtle height changes." [emphasis added]

The cumulative expansion is dealt with in a single sentence:

"A telescoping tube, similar to the boxy ones used to access airplanes at airports would be needed at the end stations to address the cumulative length change of the tube."

But that's not enough. The entire track near the ends is moving by this amount. That means that the ends of the track are advancing and retreating over multiple pylons (unless you can figure out a way to cantilever the track over 300 meters). This is a completely unsolved problem.

How about you also copy the sentence that lies just between those two?

"As land slowly settles to a new position over time, the damper neutral position can be adjusted accordingly."

And if that doesn't work, the tube can have some kind of rails or just to roll over wheels on top of the pylons. (my own thoughts as non expert)

Rocket engineers with advanced simulation tools[0] have been working on this for 5 months before releasing the paper. Do you really think they somehow missed this obvious issue?

[0] https://www.youtube.com/watch?v=vYA0f6R5KAI

Edit: Further in the paper it says: "The tube will be supported by pillars which constrain the tube in the vertical direction but allow longitudinal slip for thermal expansion as well as dampened lateral slip to reduce the risk posed by earthquakes."

So pretty much what I've said. The other quoted sentence refers to placement of pylons themselves.

I'm not this kind of engineer, but couldn't the pylon problem be addressed by a sliding rail mechanism between the pylon and the sealed tube? Or replicating the station mechanism at each pylon? Maybe I just don't see the problem you're pointing out.

edit: in retrospect, I can clearly see the problem with expanding shaped tracks.

What happens to a long S-shaped track? Think about expanding each segment of the top curve... the turn radius increases and as does the length of the turn. How do you support a tube that can get longer, move outwards along the curve, and change angles at various points? S is just an example, it seems to be a problem with any number of turns (including 1)...

I suppose one option is to simply put it underground to stabilize ambient heat input, and use heat extractors to manage heat generated by the train. If the system shuts down, there might be some thermal contraction but that's easier to manage (it's OK for track segments to separate when trains aren't running - just warm them up before operation)

Maybe move the S shape from the horizontal to the vertical plane. Then, you can handle the bend by dynamically changing the height of the pylons.

It's still an issue that at bends of this diameter, the approximation sin(x) = x is pretty accurate, which means it takes 300m of height difference to deal with 300m of thermal expansion. It might be workable to change that to e.g. 100 bumps of 3m.

sealed telescoping tube between pylons then?

That sounds really expensive.

At this pressure you can use regular o-rings, which already come in standard sizes up to a dozen meters across. They're very affordable. I still doubt they'll be necessary.

Yeah, Elon Musk never thought about that because he was busy landing rockets.

Come on.. why do you think he did not think about that?

By the way, curves in the track can eliminate this when they can slide a little. And I can imagine there are more and better solutions.

Elon can get things wrong. He already said after he had announced and hyped hyperloop he had to delay the white paper because it turned out his initial idea just didn't work and he had to come up with a new one.

In 2016 he said we would have full level 5 autonomy in self driving cars within two years. That means in all driving conditions a human could handle.

That seems exceedingly unlikely.


> why do you think he did not think about that?

Because this issue has been brought up many, many times since the Hyperloop paper was first published and no one has yet proposed a viable solution.

> curves in the track can eliminate this when they can slide a little

But you can't curve the track. The track has to be very nearly straight or the G forces become intolerable.

This is the thing: lots of people glibly propose what they think is a solution, but none of them actually work.

Elon has proposed a solution as others also already comented.

And why would large diameters not work?

> Elon has proposed a solution

Really? What is it?

I am curious, does an expansion joint not help here? Is it impossible to make an expansion joint that deals with the kinds of pressure involved?

Expansion joint is likely the way to do it, but I'm not aware of vacuum expansion joints of that size. Even if it's possible, it sounds very expensive to make and to maintain. Just like everything in this project.

That's the thing about Hyperloop. It's not technologically impossible. It's just not economically viable.

> That's the thing about Hyperloop. It's not technologically impossible. It's just not economically viable.

That's probably why this is an idea from Elon, not from the industry. The guy has a habit of forcing the market itself to accept beneficial ideas, and in the process they become viable.

Many replies mention expansion joints. There are also other techniques that can be used: for example pre-stressing as is done with continuous weld rails:


Overall, it is not a particularly difficult engineering problem.

Expansion joints are available since decades.

Not ones that will hold a vacuum.

Did you try googling? Here's a whole bunch: http://www.metraflex.com/metal-expansion-joints/

Let me be more precise: not ones that 1) will hold a vacuum and 2) are available in the 3+ meter diameter that the hyperloop requires and 3) provides the smooth inside surface that the hyperloop requires and 4) are economically viable.

This kind of Hyperloop criticism is commonplace, but strikes me as intellectually lazy. Did you read Robotbeat's link? Particularly with respect to to the MNLC Bellows Expansion Joint.

> 1) will hold a vacuum

Plain wrong.

> 2) are available in the 3+ meter diameter that the hyperloop requires

This is a simple manufacturing problem, although calling a "problem" seems like an overstatement. Obviously not everything to build a Hyperloop is wholly off the shelf. If there is some reason why this can't be built in larger diameters, then that's certainly not obvious.

> 3) provides the smooth inside surface that the hyperloop requires

The Hyperloop runs on an air cushion. It's a hovercraft. Millimeter-scale bellows ought not to be a problem.

> 4) are economically viable

And here, you could be entirely correct, and is why I'm not yet a Hyperloop true believer. I'm not wholly convinced that this kind of machinery can be economical over its whole life-cycle in its intended service environment. But proving that this is the case requires more than glib, hand-wavy assumptions. You need to run the numbers. I have yet to see any Hyperloop critic do that in a remotely convincing fashion, whereas there are many Hyperloop engineers who most assuredly are running numbers. Maybe those calculations are wrong, but the only way to refute them is with better calculations. Anything else is just dogma.

RE 4, there are also two "kinds" of economical viability: the fundamental one, derived straight from physical limits, and the usual "market couldn't be bothered with it" one. Knowing Musk's companies, he cares only about the former, and is willing to push through the latter. Thanks to that, fully electric cars with reasonable range are now not only a possibility, but a desirable product every other car company wants to build too.

The number crunching should tell in which category of viability Hyperloop is.

Just so. In the 1990s I was part of a group called the Space Access Society, which was a bunch of cranky but idealistic rocket scientists (and enthusiastic amateurs; John Carmack was a constant presence with his Armadillo Aerospace) trying to foster cheap access to space by any means possible.

These efforts were regarded with huge levels of skepticism / disinterest / dismissal from NASA and the mainstream aerospace industry, which consistently confused the second kind of viability with the first. When these people couldn't raise and/or manage the funds to actually implement their ideas, this was regarded by many as proof of the physical impossibility of cheap access to space. Most of the industry regarded them as crackpots.

Then Elon Musk came along and proved the crackpots right and the industry wrong. He could do this because physics was on the side of the crackpots and always had been, even if the market was not. That's a necessary but not sufficient condition; what he also needed -- and just barely had -- was the financial resources and organisational capacity to go up against the market and win.

There are aerospace forums[1] where one can still find smatterings of the old guard insisting that Elon Musk is just a smoke-and-mirrors phenomena; that spaceflight will always be intrinsically expensive because physics (in a hand-wavey, strictly no-calculations kind of way) says it must be so; that the only reason his rockets are cheap is because he's underpaying his workforce and working them to death; that it's impossible to re-use a rocket -- seriously, they're still saying this, even after it's been done three times already; that the Shuttle proved that reusability can never lower the cost of spaceflight, etc. etc. etc.

Some of these people have PhDs in aerospace engineering; some of them have worked on the space shuttle. No matter: they're in the throes of a cargo cult, and they're wrong. Physics are right.

Do the numbers. Engineering is done with numbers. Analysis without numbers is only an opinion.[2]

1: forum.nasaspaceflight.com/index.php

2: http://spacecraft.ssl.umd.edu/akins_laws.html

Thank you for posting this. With all kinds of matter-of-fact comments confidently declaring the impossibility of feasible hyperloop implementations, a lot of those arguments turn out to hinge on random, idiosyncratic details that are not at all the dealbreakers they're made out to be.

HyperLoop does NOT run on an air cushion (remember, the entire tube is supposed to be nearly evacuated!), but instead floats on a maglev track.

He's also missing another requirement: 5) The entire track, including any possible expansion components, valves, inspection hatches, etc etc etc have to be at least mildly tolerant to intentional or accidental damage. Running into a sudden wall of air at 700mph is a good way to destroy any passenger craft in the system.

That depends on the design. In Elon's original paper hyperloop the vehicles have an air bearing.

I am not an engineer. Is it impossible to create one? If a tube is a vacuum, then the tube moves, I don't think that negates the vacuum or does expansion and contraction make a vacuum impossible? I wouldn't believe so.

Impossible not. But expensive. And hyperloop is supposed to be cheaper than HSR.

Not with that attitude.

Your comment may seem flippant, but honestly it seems like people are more eager to be right than aspirational these days.

It's not about being right, it's about pure attitude - "why this can't work" vs. "let's talk how can we make this work".

I don't think people are actually that defeatist. If it came to a difficult situation in their own lives, I bet they'd rise to the occasion, but they'd rather see others fail than succeed greater than they did.

Is there any material available with a negative expansion coefficient that can be used to offset this?

I ask because that’s how you tend to work around thermal effects in electronics.

An electronic device contains many orders of magnitude less material than a hyperloop track. There are all kinds of materials that are economically viable when measured in micrograms. Hyperloop track material has to be bought by the kiloton.

Just to clarify - is the thermal expansion issue both in terms of the length of the hyperloop and the inside diameter of the tube, or just the length?

Relevant discussion of thermal expansion with high speed tracks: http://boards.straightdope.com/sdmb/showthread.php?t=471152

It's a combination of things: the length, the fact that it has to hold a vacuum, and the fact that it can't make tight curves. If any one of these things weren't true the problem would be easy. But they are all true, and that makes it really, really hard. (Oh, and it has to have a smooth inside surface, and it has to be manufacturable at a reasonable cost.)

We could replace steel with a low coefficient metal matrix composite without sacrificing stiffness or long range strength. It would blow out the cost structure however ;)

Have also heard anecdotally that condensation in the tube could be a real problem. Even at near vacuum, the rapid pressure differentials can cause buildups in front of and behind the speeding vessel.

> It would blow out the cost structure however

Sure, all of these problems are solvable if you are willing to expend arbitrary resources. But the whole point of this exercise is to provide an economically viable mode of transportation. (Isn't it?)

This is only if the tube sections all move together. This could be handled at the joint between each tube section, and then the joints would only have to move a fraction of that distance.

Compressable joints between each section?

Musk has addressed this:

Similarly, the proposal briefly discusses thermal expansion: as the steel of the tubes heats in the hot California sun, the metal expands. That expansion needs somewhere to go. In high-speed railways, rails are allowed to overlap at the ends, but that’s not possible in the Hyperloop, and so Musk has a different solution:

“Specially designed slip joints at stations will be able to take any tube length variance due to thermal expansion,” he explained. “This is an ideal location for the thermal expansion joints as the speed is much lower nearby the stations. It thus allows the tube to be smooth and welded along the high speed gliding middle section.”


I think the hand-wringing over expansion is a bit over the top right now. Seems like its a relatively solved problem and one the Hyperloop team is taking seriously. I imagine the cost of engineering and building giant slip joints is just part of the overall cost package and probably a non-trivial part. I find it hard to believe someone as relatively trustworthy and technical as Musk is selling this concept knowing full well its impossible.

Most likely, this is a solvable problem the same way many difficult problems were solved for cars, planes, and rails during their inception. I read an analysis somewhere that the Wright brothers solved 4 or 5 'hard' problems with their first plane. Their competitors at the time weren't able to solve even one. I'm not saying Hyperloop is guaranteed to work, but declaring it 100% impossible seems overly pessimistic.

My worry is a bit more prosaic, if we gain progressive leadership in congress, we may be looking at Euro-style high speed rail in many US regions, which would invalidate the hyperloop concept. This seems less likely, imo, but by far the saner move.

Does he not realize that you can't just take up all the slack at the ends? That would mean the pylons nearest the station would be pushed over around 300 feet. How would the hyperloop stay elevated without pylons?

Why would the pylons need to move? You can essentially have tube sitting on top of the pylons (which I expect could have ~50 degrees of contact area). You could even have it sitting on rollers between the pylons and the tube.

When are we going to address the elephants in the room?

Just the tube alone:

  - largest pressure vessel in the world. How do you keep it at near vacuum?
  - Thermal expansion over such a large distance, especially if the top of the tube is warmer than the bottom.
  - Safety, how does an evacuation look like if the tubes are sealed?.
There are many more. Some how I feel like this is a "pipe" dream. Lots of marketing, very little engineering.

> Lots of marketing, very little engineering.

It started as a technical whitepaper, not a marketing campaign, and multiple companies are building experimental models. I don't think this critique is accurate or fair. There have been far worse vapourware and hype-only concepts that haven't gotten close to hyperloop's tangible progress.

No tech can be perfected from the planning stage either, it takes talent, money, and time - and you can't get those things without a bit of hype, the key is keeping it balanced.

Regardless the concept seemed feasible enough to some very smart people and people with money to spend, where they see it's worth the R&D.

I don't really see what the big risk or downside here of exploring this? Considering the rewards could be very high if it does work and otherwise there has been little innovation in transportation in 50yrs, it's not like there are some obvious alternatives are being neglected.

>it's not like there are some obvious alternatives are being neglected

A high speed train like the ones they've had in Europe for a long time? You know, the ones that regularly reach 300 km/h? If that's not fast or flashy enough for you, what about Maglev? It actually exists, and the tracks are extremely expensive even though they don't even have to maintain low air pressure

> A high speed train like the ones they've had in Europe for a long time?

I don't see what the US political inability to build infrastructure has to do with my comment. Plenty of countries are still building highspeed trains and iterating on that model... and plenty of non-US countries are looking into hyperloop, the first ones to adopt it will likely be outside of the US, as that's where most innovation is these days. And regardless there's always plenty of room for new ideas.

Unless you think these billionaires should be backing American transportation mega-projects instead? There's plenty of roadblocks there outside of access to capital, where a highspeed train will likely cost 2-3x the initial projections, even if a private company does it. Not to mention the US is a car-heavy market. It seems like a risky project for any non-government entity to take on as it will be packed full of political risk and direct involvement either way...

The US rarely builds major projects anymore except in the defense industry. And almost every major defense project of comparable size ends up being billions over budget or cancelled.

We have natural gas pipelines that have to maintain a far higher pressure difference, and they are in the same order of magnitude in diameter. They're not expensive. Way less than high speed rail lines per mile.

No, the whitepaper came after the start, which was Musk publicly bragged about how he and his engineers could do the rail project better.

"More marketing than engineering" seems accurate to me.

The pressure tube doesn't need to be at near-vacuum. By the drag equation, air resistance is proportional to pressure; merely cutting pressure by 90% would reduce air resistance by the same amount, and that's trivial with perfectly ordinary pumps.

Serious vacuum pumps are not required. This is not to say that keeping it airtight won't still be a major engineering problem, it just isn't as near-impossible as near-vacuum would be.

To cope with expansion, you'd need to use sliding plates--which, yes, will make it harder to keep the air out. That's going to be an interesting challenge.

Doesn't the Hyperloop concept rely on not having a perfect vacuum? It's supposed to suck in air on the front and blow it out the bottom as an air cushion. Without the air cushion you just have "maglev in a vacuum" instead.

I'm sure that's also a fast mode of travel, but like you said, the vacuum part of it takes a lot of money.

Does the vacuum part take a lot of money? I would think that if anyone knows, it'd be someone like Elon Musk who has built a spacecraft company from the ground up.

For many of Elon Musk's projects, I get the idea that Elon is mostly just bringing broad, multi-domain knowledge to bear on industries that have been siloed for a very long time. So everyone scoffs at a long vacuum tube and using turbomachinery, etc, but for someone with a physics background with extensive knowledge of the spacecraft environment, turbopump rocket engines, and all the subsystems and ground testing systems that enable all this, it really isn't far-fetched at all. Most physicists (of the experimental kind, i.e. those who have to have hands-on knowledge fabricating things in addition to theoretical background) that I've talked to understand his ideas and think they're fairly reasonable.

People seem to base most of their criticisms on the fact that it's different than what we already do without a fundamental, first-principles understanding of the system.

A real vacuum (or very close to it) would be expensive, yes. That's what Musk designed the hyperloop to avoid; it works with a "low pressure" tube instead. His original hyperloop proposal paper outlines this in the intro:


Another extreme is the approach, advocated by Rand and ET3, of drawing a hard or near hard vacuum in the tube and then using an electromagnetic suspension. The problem with this approach is that it is incredibly hard to maintain a near vacuum in a room, let alone 700 miles (round trip) of large tube with dozens of station gateways and thousands of pods entering and exiting every day. All it takes is one leaky seal or a small crack somewhere in the hundreds of miles of tube and the whole system stops working.

However, a low pressure (vs. almost no pressure) system set to a level where standard commercial pumps could easily overcome an air leak and the transport pods could handle variable air density would be inherently robust. Unfortunately, this means that there is a non-trivial amount of air in the tube and leads us straight into another problem.

The "another problem" being that if you just do low pressure, it means your pod has air in front if it and has to pushing that air around (or if that air has nowhere else to go in the forward tubing, trying to compress it, because not enough of the air can squeeze around the pods at the edge of the tube). That's what the hyperloop is getting around by sucking air in the front and blowing it out the bottom. Working as an air cushion is something of a bonus, and if everything works out right it also lets you avoid the expense of maglev.

I haven't done any work on hyperloops. But expansion seems to be a problem already solved by industry a long time ago: https://en.wikipedia.org/wiki/Metal_expansion_joint

Sounds promising:

- Resistance to high and very high pressures

- Large movement absorption

- Early leak indication (in case of damage) via standard check hole

- Complete burst resistance

- Possibility of permanent leak monitoring in critical media

Metal expansion joints can't hold a vacuum.

The CERN LHC tube is a 27km circle of vacuum and near-zero temperature, and they don't seem to have a problem with that (granted, they had some but it's solved now).

Frankly, yes, there may be issues, but I'm confident that the Human race will be able to overcome those.

The LHC's vacuum pipes are 6.3 cm in diameter..

Yeah, LHC's is the largest in the world at just 15,000 cubic metres -- equivalent to about 1 km of hyperloop tunnel (assuming 14ft diameter mentioned in the Boring Company's FAQ)

What, really? What's with all those mega photos we see everywhere ?

This picture shows a cross section of part of the LHC. Those two yellow lines sticking out are the actual tubes. Everything else is equipment to manage the particles (detectors, containment, magnetic propulsion).

And for a sense of scale, a human can comfortably stand in that tunnel next to it.

Image: http://www.tut.fi/cs/groups/public_news/@l102/@news/@p/docum... From here: http://www.tut.fi/en/about-tut/news-and-events/tut-and-cern-...

Most of that is the magnets around the beam tube, with the associated power and refrigeration equipment. The beam tube itself is quite small.

Those are the detectors. And the magnets around the tubes.

What about building a high speed train? Proven technology, works in a lot of countries. LA to SF in 2 hours. Is it really that bad?

Someone made the argument that in the US our rails were built by men half killing themselves for low wages and with very few safety standards. That means a modern buildout is much more expensive than it was historically and the political will to build that budget is difficult or impossible.

Hyperloop is a run around that problem. Largely autonomous/low staffed boring that's non-union labor, non-public sector can make a lot of progress quickly. There's no public sector union demanding x amount of jobs, x amount of pensions, and other expensive regulations or union concessions. Musk's Boring Company thinks it can build tunnels for a fraction of the cost privately without much public sector regulatory weight and they might be right.

HSR is the saner idea, but without Congress funding it, its just not going to happen. Obama made a big push for it during the stimulus but more conservative states decided against accepting the money for both ideological and financial reasons. Once enough states say no, then the rail can't go very far, and the project eventually died:

First, Tea Party conservatives in Florida and wealthy liberal suburbanites in the Bay Area began questioning their states’ plans. Then, just as Joe Biden was calling for $53 billion in high-speed-rail spending over the next six years, a crop of freshly elected Republican governors turned down billions in federal money for lines in Wisconsin, Ohio, and Florida. Finally, Republicans in Congress zeroed out the federal high-speed rail budget last month.


Re: unions, there are sandhogs unions, wouldn't they be relevant? Ex: http://www.sandhogs147.org/

It'll be more like 3 hours, and it will end up costing around $100 billion. It would be dramatically cheaper and faster to subsidize free plane tickets between LA and SF for the next 50 years.

HSR works well in places with high density and competent infrastructure construction strategies. California has neither.

Trains have a much higher capacity. Most people currently drive the distance which leads to more accidents and a lot of lost time.

$100bn is too expensive to make sense but I don't understand why it should cost that much. There are not that many tunnels needed, esp. if you start/end north of LA and south of SF. European rail projects are also expensive but still a fraction of the cost.

I love how you've capitalized "Human", as if to say there were some other race competing to complete the Hyperloop. :)

Thermal expansion is at least easy to manage if your system is kept near 0K in operation. It's only an issue when the system is turned off.

It's easy to come up with reasons why something won't work.

But, usually, it's more productive to start with the understanding that other people are smart too, and that they may have thought of these problems. In this particular case, I believe that the original white paper addresses these points. I'm not a structural engineer, so I've no idea if their solutions are valid and I'm not saying that it's never okay to criticize, but this reads to me as if you may have fallen into the trap of forgetting that the people who designed this are very smart people, and thus likely thought of the obvious problems.

Out of curiosity, have you ever built anything big? I say this because the tone of your comment is dismissive, however it seems quite low-effort. I can translate your criticisms into criticisms of building subways in 1863:

  - if you build a subway it will be the biggest underground railway ever built.
  - Rocks.  They could fall in front of a subway car and cause a huge accident.
  - safety.  what if all the lights and power go out?  Also how would anyone breathe down there.
And my criticisms seem stronger, not weaker, than yours. Today all cities with robust subway systems benefit hugely from them and all of these issues have been resolved.

The criticism you've offered seems equally low-effort, so this is why I'm curious if you've ever helped design and build any large-scale project.

I don't like gratuitous negativity on HN and it's against the rules here.

Also, planes are a terrible idea. I mean how do you evacuate people from them if something goes wrong? I think this whole airplane thing is just vaporware.

That isn't exactly a solved problem though. Almost all of the time it's "everyone dies". We just have failure rates low enough and it's convenient enough that people accept it.

This is normal. You either handle failure gracefully or ensure the failures are very rare.

The question isn't "will this ever work?", the question is (while keeping with your airplane analogy) is Elon Musk's design closer to the Wright brothers airplane or Da Vinci's ornithopter. I'd guess the latter personally.

The Wright brothers had a bicycle shop, whereas Da Vinci was more of a painter.

The main thing Musk has in common with the Wrights is running an electric car transportation company and sending private rockets into space via SpaceX.

I think you should revisit whether that makes it more Wright brothers or Da Vinci.

What are you arguing? You wouldn’t take the position that it’s guarenteed to succeed, that seems absurd to me. The person you replied to only made the point that it could fail. And in your reply you actually took the opportunity to degrade artists and thinkers, which seems cruel and unnecessary.

You’ve found a flaw, I think a pedantic one, in the example they gave.

Here’s an example that is less flawed, and I think if you had considered their point rather than sought minute flaws you could see this yourself: the palm note vs the iPhone. Hopefully, even if my analogy is not literally flawless, you can take my point.

Also, sorry for spamming you, something you wrote struck me and I wanted to see what else you wrote. Hope you don’t mind this.

The question is if we want to accept the risks. In the early days of subways, trains, planes and cars, accidents were frequent and many people died until we figured out the safety aspect. Today's society is much more risk averse. I don't think the general public would accept several fatal crashes before the system is safe.


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