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.
- 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.
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).
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.
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...
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.
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.
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.
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.
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.
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.
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.
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.
Seriously? What, he flipped a coin a million times which determined what he's going to do next? How are you defining "luck"?
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"
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.
"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."
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.
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.
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).
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.
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'.
Yes, golly gee, what HAS he done.
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!
That's okay, I appreciate you loaning us John Oliver. ;)
1 - https://en.wikipedia.org/wiki/Richard_Branson#Early_life
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.
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.
1 - https://www.youtube.com/watch?v=47fqjA8CwGE
Minded me of the sort of criticisms he'd level at the likes of BA back in days of yore...
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!
There should be an allowance for balance and humanity in HN comments. Not everything need be ultra-violet literal on the spectrum!
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.
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.
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.
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...
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 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.
I think it's on-topic whenever hyperloop is on-topic.
Why is hyperloop's viability nil and nonexistent?
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.
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.
 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.
 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.
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.
- 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.
Branson is notorious for burning other peoples’ money. Look at Virgin Galactic: it’s New Mexicans’  and Floridians’  tax money plus some duped Emiratis . (They also pre-sold tickets .)
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.
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.
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?
Just because I felt like doing some more Google-fu, I found an article in the LA Times 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. 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.
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?
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.
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.
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).
My guess would be that the cost of land in the north-east, combined with AFAIK pretty strong ownership rights, makes it that expensive.
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.
> 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.
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.
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).
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 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.
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.
Consider he did this with rockets, getting them to under 1/10th the cost
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.
 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)
The GAO cites $164M/launch as the price for the cheapest Delta V (is there some kind of threshold at $165M?), which when the Falcon 9 was introduced could put 8,500kg to LEO, 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!
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.
Hence the boring company.
Tunneling gets cheaper due to <...>? I would be interested.
I guess the Swiss would be interested too.
"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."
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?)
Should be "Das ist nicht gut".
 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.
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.
Sure, but these have to hold a vacuum. No one has figured out a way to do that.
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.
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.
Not sure if the same thing will work at larger scales, but I'm not sure its a fundamental problem.
"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.
"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 have been working on this for 5 months before releasing the paper. Do you really think they somehow missed this obvious issue?
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.
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)
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.
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.
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.
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.
And why would large diameters not work?
Really? What is it?
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.
Overall, it is not a particularly difficult engineering problem.
> 1) will hold a vacuum
> 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.
The number crunching should tell in which category of viability Hyperloop is.
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 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.
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.
I ask because that’s how you tend to work around thermal effects in electronics.
Relevant discussion of thermal expansion with high speed tracks: http://boards.straightdope.com/sdmb/showthread.php?t=471152
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.
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?)
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.
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?.
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.
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
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.
"More marketing than engineering" seems accurate to me.
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.
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.
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.
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.
- 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
Frankly, yes, there may be issues, but I'm confident that the Human race will be able to overcome those.
And for a sense of scale, a human can comfortably stand in that tunnel next to it.
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.
HSR works well in places with high density and competent infrastructure construction strategies. California has neither.
$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.
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.
- 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.
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.
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.
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.