Hyperloop - <AUTHOR> http://www.spacex.com/hyperloop <comment><USER2> This is very serious first proposal.

As a professional mechanical engineer I have worked on high quality steel tubes (nuclear submarines) before. The immediate thing that sticks out to me in this proposal are the tight mechanical tolerances that have to be maintained. Talking about tens of thousandths of an inch tolerances on a 10' diameter tube is not to be dismissed lightly. That is going to be tough to maintain - especially with welding heat distortion. I would image the tubes will be joined with automated friction stir welding or something similiar, but that will still require a fair amount of post weld machining which has its own pitfalls. Not to mention simple thermal expansion and contraction as the temperature changes could change the circularity and inner diameter.

I would be more interested to see a tolerance stack up of those considerations than an FEA model of the concrete pylons. I can gaurentee that we can build concrete pylons capable of holding up a steel tube, that is done all over the country dozens of different uses cases. But can we build a multi-hundred mile long steel tube to the required tolerances?

I would be inclined to trade off efficiency for manufacturability. I.e. maybe a higher internal pressure or larger diameter to make it less sensitive. There should be plenty of power from the solar panels so it doesn't have to be perfectly efficient.

I'm also surprised that the I-5 plan is cheaper than buying private land. I may be naive here, but the pylons really do take away most of the objections from farmers and installing tubes over farmland has to be a lot cheaper than doing construction above a highway. I just look at boondoggle that was the SkyTrain in NYC (tram running over a highway out to JFK airport) and wonder if that is a great option.

<comment><USER3> > I would image the tubes will be joined with automated friction stir welding > or something similiar, but that will still require a fair amount of post > weld machining which has its own pitfalls

The document mentions standard orbital seam wlelding, plus specialized machining equipment that travels along the tube to smooth out the gliding surface.

The capsules are only 60% the diameter of the tube, or 36% it's area (68/47% for the vehicle-carrying version), it doesn't seem to require tight tolerances for operation. I got the idea that tube distortion and movement is taken into account into the system.

<comment><USER4> > _it doesn 't seem to require tight tolerances for operation_

Well, it's true that the top and sides of the tube don't get too close to the capsule, so those parts seem relatively low-tolerance, as you say.

But the load-bearing skis ride on an air bearing of 0.5mm to 1.3mm (see page 20), moving at over 1000km/h. As rossjudson notes, the skis are on mechanical suspension, to smooth out shocks to the riders, but it's not clear (to ignorant me) how much of a bump those skis can glide over. 0.1mm, no problem. What about 1.0mm?

On a related note, Musk seems sanguine about the sag you'd get in any structure supported by pylons (see e.g. page 27). Even with inch-thick steel walls, with pylons an average of 30m apart (100'), you'll see _some_ sag, right? Any engineers want to comment on the deviation in 30m of inch-diameter- wall steel tubing? Let's see, 1200kph, 30m, so you pass a pylon 11 times per second. So in 0.09 seconds, you have to go from the top of one pylon, to the valley between two pylons, and back to the top of the next pylon. I guess that's all absorbed by the mechanical suspension?

<comment><USER5> You could just build the tubes bending upwards slightly, so that the sag will pull them straight.

<comment><USER6> No you could not. The steel tube will expand and contract as temperatures change. Along most of the route, that longitudinal movement of the tube will be in the 10s and 100s of feet, which means that the "valley" could be anywhere on the tube according to temperature.

<comment><USER7> Also, tubes will resonate and vibrate as vehicles go by. This could be actively damped at the pylons though, like they already considered doing for ground subsidence.

</comment></comment></comment></comment></comment></comment><comment><USER8> "In the case of the Hyperloop, Musk started focusing on public transportation after he grew disenchanted with the plans for California's high-speed rail system."

And who says that big government stifles entrepreneurial innovation?

If ALL Musk does with the Hyperloop announcement is shed more light on the potential debacle that is to be our $70b+ high-speed rail in California, we owe him a debt of gratitude.

PS - Direct link to the Hyperloop plans .PDF [http://www.spacex.com/sites/spacex/files/hyperloop_alpha-201...](http://www.spacex.com/sites/spacex/files/hyperloop_alpha-20130812.pdf)

<comment><USER9> Interesting point that big government provoked the advancement of the hyperloop idea - counterintuitive idea, and clearly yes. but any idea like this will need government cooperation. The real test of big government will be how they respond to the hyperloop.

magic response: "of course we may be wrong, we'll look into this immediately." and then they decide to build it.

likely answer: praise, perhaps even an evaluation, then disregard as unrealistic a year from now.

why would "big government" ignore this idea? fairly simple: risky and unproven, for a politician, in a career where risk is not related to upside; and probably more important is the ability to control $70bn in spending to private citizens and contractors - far more valuable to their careers (leading to donations and influence) than spending a smaller amount (a mere $7bn) on fewer contractors. For the most part, the hyperloop contractors would not be the same guys who have been donating to politicians for the past decade in support of the train.

so yes, big government and the natural corruption of a large budget (donations->spending with favored constituents) will likely lead to the status quo - a ludicrously overpriced train.

as far as political repercussions, california is not a two party state any more, so there's no one to capitalize on the idiocy of the folks in power. i guess, we reap what we sow.

<comment><USER10> It was approved by a ballot measure, so in this case it may be the "idiocy" (or will) of the voter.

[http://ballotpedia.org/wiki/index.php/California_Proposition...](http://ballotpedia.org/wiki/index.php/California_Proposition_1A,_High- Speed_Rail_Act_%282008%29)

<comment><USER11> They approved it at a much lower budget ($9.95 billion). It would be interesting for the voters to get another vote based on the current cost projections.

<comment><USER10> The $9.95 billion was for the initial bond issuance. The estimate on the ballot was $40 billion versus the current estimate of between $98.5 billion and $118 billion.

Edit: correction from dragonwriter, via wikipedia [1]:

"The cost of the initial San Francisco-to-Anaheim segment was originally estimated by the CHSRA to be $33 billion (2008) / $35.2 billion (2013), but a revised business plan released in November 2011 by the CHSRA put the cost at $65.4 billion (2010) / $68.9 billion (2013) / $98.5 billion (YOE). The latest plan has revised the costs down to $53.4 billion (2011) / $54.5 billion (2013) / $68.4 billion (YOE)."

[1] [http://en.wikipedia.org/wiki/California_High- Speed_Rail#Fund...](http://en.wikipedia.org/wiki/California_High- Speed_Rail#Funding)

<comment><USER12> Those numbers still seem absurd to me. $120 billion? France built the entire TGV network, about 2,000 km (1250 miles, ~2x the length of LA-SF, including numerous stations in urban areas) for around $20-30 billion. Maybe the U.S. should borrow some management practices from inefficient socialist "old Europe".

<comment><USER13> Uh, the number above is $70b and the TGV was built 30+ years ago so you could at least double that number based on inflation.

<comment><USER12> Even the most expensive TGV lines, have a per-km cost of around $20m/km in present dollars, and that's high enough to cause controversy. The bulk of the network was built for prices of $2-4m/km at the time, which is about $3-5.5m/km if you adjust for inflation. For a 700-km line like SF-LA, even the $20m outlier cost would work out to only $14 billion. Where's the 8x multiplier coming from? No TGV line has cost >$100m/km, or even close, in 2013 dollars. I am not sure any line in the world has cost that much, even in inhospitable terrain like China's high-speed rail in Tibet, or Japan's high- speed rail through the mountains.

<comment><USER14> France probably doesn't tie both its rail agency's hands behind its back with pointless environmental impact reports (the sole purpose of which seems to be to generate extra revenue for civil engineering contractors) and then let NIMBYs sue because this or that insignificant detail wasn't included.

<comment><USER15> France is an interessting case. If I remember well, the have a group of people (project managers, politians, you name it) preparing the case well before any actual construction work starts. Yet, as afar as I remember, there actually were some controversies when they started a TGV line somewhere in northern France. But it still works pretty well, one benefit of being highly centralized.

Another factor at play is that TGV lines are purpose built for high-speed traffic (curve radius, climb rate, ...) while for example in Germany they are mostly shared. That makes the single TGV track cheaper, but you still ahve to built another track for lets say freight. If want another track, that is.

But the cool thing ist that TGV don't stop at every single village that happens to be the hometown of some polititian.

<comment><USER12> I think one aspect is just that the decision is made definitively at some point, in advance. People have different opinions: impact on historic buildings, noise, environment, other things. This is all debated up front, and then the legislature either approves it, or it doesn't. But when it was approved, it was approved. You can't sue in court to stop the plan on environmental grounds or noise grounds or something else, once the legislature has decided to go ahead with it, because the authorizing legislation supersedes any contrary legislation.

But the U.S. delegates decision-making to agencies and courts in a way that this doesn't happen. California might take input for a long time before deciding on its plan, but its final plan is still not final. Anyone can sue it for many different reasons. Maybe it violates the federal Clean Air Act, maybe it violates property rights, maybe something else. The decision is never final until every challenge to an agency or court is decided, which massively adds to uncertainty and costs.

</comment></comment></comment></comment></comment></comment></comment></comment></comment></comment></comment><comment><USER16> I am intrigued, but not overwhelmed. Many of his reasons why his hyperloop is superior to high speed rail are not specific to the hyperloop. For example, you can put railway tracks up on pylons, too, with very little impact on the ground. It is common to do this in urban areas, but it is rarely done in rural areas because it is flat out cheaper to put it on the ground. I don't believe that an experimental tube is going to be somehow magically cheaper and easier to route and build than train tracks.

Now, I am not trying to defend California's HSR, specifically. I agree with Musk that it appears to be very poorly done. However, the answer, to my mind, is to do it properly rather than propose a wild experiment with hand-wavy arguments as to why it would be politically easier to do. Do you really think the special interests that are making HSR so difficult and expensive would say, "Oh, do whatever you like with your tube."?

Now, in an attempt to end on a positive note, I do like his proposal as a possible next step beyond HSR. Rail can go up to 350km/h currently (perhaps more in the future--why wouldn't California design with this goal in mind?), but Musk's hyperloop is proposed up to ~1000km/hr. It is definitely an idea worth exploring, but I think it falls far short as a serious alternative to the current high speed rail plans.

<comment><USER17> _I don 't believe that an experimental tube is going to be somehow magically cheaper and easier to route and build than train tracks._

 _Do you really think the special interests that are making HSR so difficult and expensive would say, "Oh, do whatever you like with your tube."?_

These are extremely important issues that advocates seem to be glossing over. Putting the guideway on pylons doesn't magically eliminate land issues, you will still have to deal with visual impacts, along with any number of anticipated and unanticipated problems.

Musk should do what the Germans did with the TR0x series of maglev vehicles, build a 10-20 mile test section someplace and demonstrate that is analysis is sound.

 _(perhaps more in the future--why wouldn 't California design with this goal [350 km/h] in mind?)_

There are a variety of reasons, but one important reason I have to deal with is that the speed of shear waves through soil is only on the order of a couple of hundred miles per hour. When a train exceeds the shear wave speed, ground- borne vibration waves "build up" in a manner similar to the shock wave created in air when a plane exceeds the speed of sound, causing a ground-borne vibration equivalent of a "sonic boom" that can cause problems for wayside structures. I believe the French have started to experience this with some of their higher-speed TGV experiments and we don't have a good way to handle this yet.

<comment><USER18> > Musk should do what the Germans did with the TR0x series of maglev vehicles

Musk has already given more than enough for the world and done more than enough. Somebody should do it, but we should not expect him to do it.

<comment><USER19> We shouldn't expect him to demonstrate his idea?

<comment><USER20> I think tesla motors releasing an affordable car would benefit the world a lot more than the hyperloop. But it's nice that he is presenting the idea so the world can do their own analysis and even implement it before he has the chance.

<comment><USER21> >>I think tesla motors releasing an affordable car would benefit the world a lot more than the hyperloop.

Specifically, an affordable Tesla car could benefit the entire world, whereas the Hyperloop would (at least initially) only benefit people living in LA and SF.

<comment><USER22> What are the benefits to the world market of an affordable Tesla compared to, say, a modernized version of the Volkswagen Lupo, or a plug-in Up! ?

<comment><USER23> They both benefit the world. Fact is, there is no modernized 3-Liter-Lupo, and I've heard no rumors that there ever will be (?). Until there is, Tesla will be the one who demonstrates what is possible.

</comment></comment></comment></comment></comment></comment></comment></comment><comment><USER24> Reading the entire PDF is highly recommended; it contains a surprising amount of answers already (including many to comments below).

I think, if anything, safety aspects haven't been sufficiently explored in the pdf. I'm quite happy to believe it's safer than other modes of transport, but I wouldn't be too quick to overstate it. Also, if anyone can explain what "Tubes located on pylons would limit access to the critical elements of the system." is meant to mean in §4.5.6 I'd be grateful...

<comment><USER25> > "Tubes located on pylons would limit access to the critical elements of the > system." is meant to mean in §4.5.6 I'd be grateful...

You don't have to worry about cows wandering into oncoming vehicles like you do with cars and trains. It's also harder for non-determined people with malicious intent to interfere with operations.

A determined attacker can, of course, scale pylons. But you don't have to worry about stuff like kids lobbing bricks from overpasses, or people pushing others onto subway tracks.

<comment><USER26> the pylon could be the target to disrupt the operation

<comment><USER27> Yes, but so could tracks on any high-speed rail, and in that case with considerably greater ease. In this case, the actual railway is sealed off from all but the most determined external forces, who would be able to do just as much damage to a conventional train.

</comment></comment></comment></comment><comment><USER28> Adding a compressor fan to actively transfer air from the front to the rear of the pod while simultaneously serving as an air cushion to support the vehicle is simple, elegant and absolutely brilliant!

An ingenious solution appears so obvious in hindsight that it leads you to ask "why didn't I think of that?" While being subtle enough to confound all those who came before.

I have been following the developments of the ET3 Consortium for the past year. I have read virtually all the technical literature available online on the topic of alternative high-speed transportation systems going back as far as the RAND paper and even reading related patents from much earlier.

Looking at the genius of Elon Musk's insight is both inspiring ang greatly humbling - but mostly inspiring. Holy awesome! I would love to see this innovation take root. It could be the perfect elixer to our stagnant economic malaise.

Well done Mr. Musk!

<comment><USER3> I'm pretty sure that idea has been thrown around, maybe even here on previous HN discussions, can't remember. The hard part is having really deep knowledge of the tech involved, manufacturing and costs, and producing a 50-page technical document with input from dozens of top minds in their fields :)

</comment></comment><comment><USER29> I am skeptical of the proposed cost were someone to actually build this. Sure, the cost of materials, labor, engineering, etc. is probably accurate, but something like this has never been built before. What about the cost of research and testing? Not to mention there doesn't currently exist an industry of contractors to build most of the parts of this system, which is not true in the case of traditional high speed rails. Citing the cost to build something like the Hyperloop as the entire cost of developing it seems a bit disingenuous.

Not that it still wouldn't be comparable to the cost of a high speed rail system.

<comment><USER30> That may be true, but the only thing you really need is to find a company that is willing to build this while chipping in some of the R&D cost.

I don't think such a company would be hard to find because if they get this done, they are now the only vendor of a highly desirable technology. Pretty sure they'll be able to get back that early investment... and then some.

(And remember - Musk contrasts $6b to what he estimates could possibly grow to $100b for the current proposal, so even if they end up needing to double their budget, they'd still be off by an order of magnitude.)

<comment><USER31> > And remember - Musk contrasts $6b to what he estimates could possibly grow > to $100b for the current proposal, so even if they end up needing to double > their budget, they'd still be off by an order of magnitude.)

Why should we think that Musk's estimates for a technology which still isn't well defined (read the "Future Work" section at the end of the document) are reliable even to within an order of magnitude, and why should we accept Musk's assumption that the actual cost of the HSRA will be 50% higher than its official estimate?

<comment><USER30> Alright, safe for the fact that this may still turn out to be an impossible technology after all for something we're all missing and also for Musk being off by an order of magnitude (which I don't see to be that plausible).

Even if you worst-case Musks plan and best-case the traditional concept * , you end up in about the same cost bracket. Just that in the one case you get incredible space tech and in the other, you get a boring train that isn't even as great as it could be with 20 years old tech.

As for the "Future Work" section - I don't really see how they could explode the budget. Only two points (station design and comparison with traditional Maglev) seem concerned with R&D work - for station design, you're not really looking for any breakthroughs, just packaging and mentioning Maglev seems more like a "just make sure" point that isn't really about physical cost at all.

* This part is highly unlikely - government issued endeavors like a long distance train routes have a pathological tendency to run over budget (a few billion here and there, who's going to notice?!). Of course, the same applies to Musks concept, but _starting_ at an order of magnitude lower means that the kind of petty "I'm going to carve a piece from that cake, too" budget overruns should be well within range.

</comment></comment></comment></comment><comment><USER32> Someone needs to convince Musk to build this on the east coast of Australia; linking Brisbane-Sydney-Canberra-Melbourne. The Sydney-Melbourne air corridor is one of the busiest in the world (6,795,000 passengers in 2007, vs 6,306,638 for LA-SF in 2009 [1]). We recently had a feasibility study into HSR along the east coast (a condition of Greens support of the current Labor minority government) but it suggested that such a project would be ridiculously expensive and take upwards of 30 years to complete (some say the study was doomed to fail and the numbers are wrong).

The geography is probably less favourable for Hyperloop in the eastern Australia context (e.g. Sydney is in a basin bordered by low mountains north, south and west), whereas the route it would follow in California is mostly flat?

[1] [http://en.wikipedia.org/wiki/World's_busiest_passenger_air_r...](http://en.wikipedia.org/wiki/World's_busiest_passenger_air_routes)

</comment><comment><USER33>
        The key advantages of a tube vs. a railway track are that it can be built above
        the ground on pylons and it can be built in prefabricated sections that are
        dropped in place and joined with an orbital seam welder.

Did anyone else read this and imagine laser beams fired by satellites?

<comment><USER34> Not really. It's a valid welding [http://en.wikipedia.org/wiki/Orbital_welding](http://en.wikipedia.org/wiki/Orbital_welding)), but I imagine it might be quite a task to scale it up to pipes as large as would be needed for this project.

<comment><USER35> For some reason Elon Musk is extremely enamored of welding technology. I remember seeing a page on an old version of the SpaceX site containing a high- level overview of the Falcon 9, where they went out of the way to mention how great circumferential friction stir welding is compared to whatever NASA used to do. And here he is bragging about it being the large stir welded thing ever created: [http://www.nasaspaceflight.com/2009/01/musk-ambition- spacex-...](http://www.nasaspaceflight.com/2009/01/musk-ambition-spacex-aim- for-fully-reusable-falcon-9/). It's a revolutionary vehicle in many regards, but Elon seems to have a particular soft spot for welds.

<comment><USER36> Makes sense, most of the volume in a rocket is a tube structure. I imagine that SpaceX has spent a lot of time evaluating ways to precisely and cost- effectively build tubes...

</comment></comment></comment></comment><comment><USER37> That capsule ([http://images.bwbx.io/cms/2013-08-12/0812_Hyperloop_605.jpg](http://images.bwbx.io/cms/2013-08-12/0812_Hyperloop_605.jpg)) looks like a claustrophobic's nightmare.

Otherwise very, very cool.

<comment><USER38> what happens when you develop unexpected gastric issues mid-30 minute journey?

<comment><USER39> What happens currently on a high-speed rail system? I suppose there's a lavatory in the HSR (e.g.: France's TGV).

<comment><USER40> Currently you get up and go to the bathroom at the end of the car.

I've only had time to skim the full PDF, but there's something about experiencing 0.5g of acceleration - unsure if that is a constant or if that is simply right at the very beginning.

If you're going to experience 0.5g of acceleration over a prolonged period, letting passengers get up and move about is going to be a bad idea. It also doesn't look like there's enough roof to get about in that capsule. 0.5g doesn't sound like a lot until you think about it as 50% of your body weight tacked on, in a direction you're not used to having it tacked on. Pretty simple in a seat, much less simple trying to walk.

<comment><USER41> _> unsure if that is a constant or if that is simply right at the very beginning._

If the top speed is 700mph then you'd have 142 seconds of 0.5 g acceleration to get to top speed. How often you'd be accelerating or decelerating would depend on how many intermediate stations there are.

<comment><USER22> Curves are also specced for 0.5g. That will account for quite a bit more of the total acceleration time than just speeding up and slowing down.

</comment></comment></comment></comment></comment></comment><comment><USER42> Announcement any minute now according to Elon Musk's twitter: [https://twitter.com/elonmusk/status/366964441159438337](https://twitter.com/elonmusk/status/366964441159438337)

Edit: First article - [http://www.businessweek.com/articles/2013-08-12/revealed- elo...](http://www.businessweek.com/articles/2013-08-12/revealed-elon-musk- explains-the-hyperloop)

Edit2: Site OP linked to is up, but may be cached for you. Try [http://www.spacex.com/hyperloop?1](http://www.spacex.com/hyperloop?1)

</comment><comment><USER43> I think he should start a ticket pre-sale on kickstarter and see if he can be the first person to reach $6 billion for a project.

<comment><USER44> 30 million people donating 200 each...totally doable.

<comment><USER45> Or 3 million people donating $2000 each for huge discounts on long term access. I would donate $10,000 if the discount was steep enough on long term use and included use of future expansions of the system.

<comment><USER45> Or better yet, sell tickets at a discount that can then be re-sold when the system is complete. Someone could buy $1M of reduced price tickets and then resell them for $2M when the system is ready. This way wealthy individuals wouldn't hit a maximum investable amount based on their personal expected use of the system.

</comment></comment></comment></comment><comment><USER46> The main reason why air travel continues to be the most practical, cost- effective means of high-speed transport is that the politics involved in connecting two points with a transit system are enough to make you lose faith in humanity.

Take for instance, the DC metro system. There is an expansion underway to extend the system west to Dulles Airport, about 30 miles or so from downtown DC. A huge project, no doubt, but it is about ten years behind schedule. What was a seemingly great idea (mass transit to a major airport and outlying regions of DC) was almost ruined by all the fighting.

This is for a project spanning 30 miles. Imagine the politics and fighting that occurs between politicians, contractors, lobbyists, and residents on a public works project that spans hundreds of miles between two of the most populous cities in the world.

A project this ambitious is only well-suited for a small, independent group of like-minded people, which unfortunately will never be possible with all the interests involved.

<comment><USER47> I like to think (hope?) that when a world changing idea comes along (and if this does work as described, it definitely is world changing), everyone can work together and implement it in a reasonable time frame. I think one of the reasons many projects take so long to complete, like the California HSR, is because the cost to benefit isn't all that great. It has no advantage over flying and little to no advantage over driving.

<comment><USER48> When a world changing idea comes along, there are always parties that stand to lose from it (1). If those parties are good capitalists, they will oppose the change. That is what stops many good ideas in their tracks.

(1) yes, a change could be an absolute net win for everybody, but it cannot be a relative win for everybody. In many cases, people will prefer to have less, as long as 'the others' have even less.

<comment><USER49> [http://www.pnas.org/content/104/47/18854.long](http://www.pnas.org/content/104/47/18854.long)

and the talk about it:

[http://www.ted.com/talks/frans_de_waal_do_animals_have_moral...](http://www.ted.com/talks/frans_de_waal_do_animals_have_morals.html)

</comment></comment></comment></comment><comment><USER50> > 4.5.6. Human Related Incidents Hyperloop would feature the same high level > of security used at airports. However, the regular departure of Hyperloop > capsules would result in a steadier and faster flow of passengers through > security screening compared to airports.

Ugh. That only seems feasible if back-scatter scanners are the _only_ option (but would you still have to take your belt off and put all metal in a little bowl?).

<comment><USER51> The TSA phased out all the X-ray backscatter machines due to radiation concerns. All the scanners at airports use millimeter wave radar now. Still the same privacy concerns, but no ionizing radiation and thus no possible health concerns.

<comment><USER52> WRONG.

Such machines are still in use and besides, neither machine machine has provably been better than plain old metal detectors.

[http://tsastatus.net/](http://tsastatus.net/)

<comment><USER51> Was this CNN article wrong then? I don't travel very much, but haven't seen an X-Ray backscatter machine since last year.

[http://www.cnn.com/2013/05/29/travel/tsa- backscatter](http://www.cnn.com/2013/05/29/travel/tsa-backscatter)

</comment></comment></comment></comment><comment><USER53> A couple of points I would like to make:

* Structural requirements

The hyperloop has much less structural requirements than a traditional train. The reason is that its cars are separated, so it is 'less dense'. If a train goes over an overpass, the overpass has to be engineered to carry the weight of the rail and the train, whereas the hyperloop only has to handle the weight of the tube (30m between pylons at about 8 tons/m is 240 tons plus the negligible weight of the capsule).

The upshot of this is that the pylons can be much less invasive on the real- estate requirements. This is important because now you have more choices with regards to routes, which leads to less curvature and higher speeds. Looking at it from the reverse angle, High Speed Rail design suffered because the massive real-estate requirements imposed such a burden that route choices were compromised, and thus the projected travel time was lengthened.

* Tube manufacture.

It occurs to me that there already exists expertise in manufacturing elevated, highly reliable large diameter steel tubes hundreds of miles long. Oil pipelines. Moreover, these companies perhaps would be interested in diversifying their business away from oil.

* Development

High Speed Rail has issues, but they are political and financial, not technological. We're really just buying the technology from other countries. Much of the cost and the incredibly lengthy construction time for HSR is coming from building overpasses and the foundations for the rail, so far as I can tell.

But hyperloop is something that requires some development. This is a good thing because investors can sell that technology and get some return. It's difficult to attract private funding for HSR, but I can definitely see someone stepping forward to fund the development of the technology.

Pretty much once someone builds the hyperloop demonstration system, you'll know if you have a winner on your hands, but with HSR, you don't know if you'll be successful until the whole thing is built (and with a 2:30 travel time LA->SF, it's not going to be a slam dunk against air).

There are plenty opposed to HSR, but I see very few alternative solutions being proposed. This might be something those opposed to HSR jump onto, and it might get a lot of support quickly.

</comment><comment><USER54> _(Figure 1). The only system that comes close to matching the low energy requirements of Hyperloop is the fully electric Tesla Model S._

Shameless plug of the day :) So far it does not break too much of the laws of physics and is indeed workable.

<comment><USER55> I also enjoyed that the vehicle carrying option could hold larger vehicles "like the Tesla Model X".

<comment><USER56> Not only that, but they would also use a lot of technology that Tesla/SpaceX now has a lot of experience in: battery, eletric engines and turbines, the metal for the ski pads, etc. There's a reason why he is making the plan completely free: he has a lot to benefit if this ever really happens.

I would love to see this happen though, and to see Elon become a trillionaire.

</comment></comment></comment><comment><USER57> I love this concept!

My main concern is the air-bearing suspension system. Barring very high flow rates, the fly-height of an air-bearing system is very small. Some systems[1] fly at 5 microns, for instance. That being the case, any sort of particulate or imperfections in the tube will cause the air-bearing to 'land' with a large amount of friction. Perhaps this is alright if you're already going 700mph, but it would reduce the overall coasting efficiency of the system.

The engineer in me sees this as the most important design consideration of the project.

As an aside, I would like to see trade studies done on filling the tube with other gasses whose speed of sound is much higher than air's, allowing the capsules to travel even faster before shocks begin to form.

[1] [http://www.newwayairbearings.com/products/flat- rectangular-a...](http://www.newwayairbearings.com/products/flat-rectangular- air-bearings/air-bearings-flat-rectangular-150mm-x-300mm)

<comment><USER58> _As an aside, I would like to see trade studies done on filling the tube with other gasses whose speed of sound is much higher than air 's, allowing the capsules to travel even faster before shocks begin to form._

I don't think this is a good idea for production use, because then you have to worry about air leaks to/from the passenger compartment.

As it is, you still have to guard against explosive decompression for the passengers.

<comment><USER57> Well that's the point of a trade study: look at the cost/benefit of different gasses. Obviously one of the costs would be the increased engineering um...pressure put on the capsule design.

Your gut feeling is probably right, though, at least for this length of trip. The increased cost of a different tube gas probably won't outweigh the benefits of arriving 5-10 minutes earlier.

Now if there were a cross-continent Hyperloop system, then for segments of the trip it might be much better to have a different gas. But again, it might simply be better to invest in better vacuum pumps for certain legs of the journey to get lower drags and higher speeds.

<comment><USER59> [http://www.phy.mtu.edu/~suits/SpeedofSoundOther.html](http://www.phy.mtu.edu/~suits/SpeedofSoundOther.html)

The only ones I see that are significantly higher than nitrogen/oxygen are methane, hydrogen, and helium.

Helium is mondo-expensive. It's not cheap even in welding-tank quantities, much less in the amounts you'd need here.

Hydrogen is flammable and/or explosive (depending on mixture) and is a huge pain in the butt to keep confined (so is helium).

Methane is cheap (but not as cheap as air :-)), and we have lots of experience with keeping it confined in big pipes. However, it's also flammable or explosive.

Using anything but air is going to require some sort of complicated replenishment/purging system and an air lock at both ends, whereas air leaks just require pumping it out again.

<comment><USER60> Neon -> 2,090mph

Krypton -> 2505mph

Xenon -> 2,438mph

[http://www.wolframalpha.com/input/?i=speed+of+sound+in+neon](http://www.wolframalpha.com/input/?i=speed+of+sound+in+neon)

[http://www.wolframalpha.com/input/?i=speed+of+sound+in+krypt...](http://www.wolframalpha.com/input/?i=speed+of+sound+in+krypton)

[http://www.wolframalpha.com/input/?i=speed+of+sound+in+xenon](http://www.wolframalpha.com/input/?i=speed+of+sound+in+xenon)

But even Neon (which is more abundant in the atmosphere than Helium) would cost ridiculous amounts of money to use.

</comment></comment></comment></comment></comment><comment><USER61> High Speed Rail is still better:

            High Speed Rail between downtown LA and downtown SF:
            2 hours, 28 minutes

            Hyperloop trip between downtown LA and downtown SF:
    	1 hour from LA to Sylmar via Metrolink
    	20 minute transfer
    	35 minutes to Dublin
    	20 minute transfer
    	1 hour 10 minutes from Dublin to SF via BART
    	Total: 3 hours 25 minutes

[http://stopandmove.blogspot.fr/2013/08/hyperloop-proposal- ba...](http://stopandmove.blogspot.fr/2013/08/hyperloop-proposal-bad-joke-or- attempt.html)

 _The project also doesn 't even attempt to price the connection into LA or SF. That's where the high costs are.

Amusingly enough, the California HSR budget for the Central Valley is under $10 billion. Ie, in the same ball-park as this proposal. The reason the HSR project is going to cost $60 billion is because it has to face an uncomfortable truth; actually getting to LA and SF is expensive. Very expensive.

Is Elon Musk's s mega-announcement really just a last-ditch attempt to sabotage the California High Speed Rail (HSR) project, rather than a serious proposal to revolution travel? Something smells very fishy._

The motive is clearly there.

</comment><comment><USER62> Wow, 300 comments in 2 hours--this is reaching the limits of readability. My first thought is that this release of Hyperloop details is like the geek's version of the Breaking Bad season premiere that is being so talked about in the US (didn't see it myself).

First of all, I think it's genius how nobody saw this solution coming, despite all the speculation. Put the air compressor on the pod, and use Tesla's battery technology to power it. Seems evident in hindsight.

My biggest gripe is the non-inherent safety and thus the security issues. The evacuated tube is a real issue in my mind, and saying it will be re- pressurized in case of an accident seems dubious. Yes, like a modern jet, but planes can descend to 15,000 and people live. Also, planes don't fly at 150,000 feet (the pressure equivalent in the tube) and there may be other biological hazards other than breathing. But mainly, the vehicles are subject to the same exterior threats as airplanes, so security will need to be similar. In addition the tubes are also a target of threats, which is less of an issue with trains and not an issue with planes.

</comment><comment><USER63> I hate to be a party pooper, but I see some economic issues.

My takeaway is that while the 7 billion fixed costs will be low, the operating costs are going to be huge.

Battery packs and solar cells will need replacement. Large maintenance teams will be needed with immediate response times to fix issues such as complete seal blowouts, etc.

I think the first few years will be great! But in my opinion maintaining this system over the long term will be very, very expensive compared to slower rail.

I'm still optimistic that most of these and other issues will be worked out in the long term.

EDIT: Did he post what this tube will be made out of? How will he prevent solar degradation?

<comment><USER64> The tube is steel, shouldn't be a problem. The electronics are only a small fraction of the cost. It is mostly just the cost of the tube, pylons, and land.

</comment></comment><comment><USER65> "Hyperloop Passenger Capsule The maximum width is 4.43 ft (1.35 m) and maximum height is 6.11 ft (1.10 m). With rounded corners, this is equivalent to a 15 ft2 (1.4 m2) frontal area, not including any propulsion or suspension components."

At a first look I didn't get that the proposed passenger capsule would be so small. That's pretty cramped.

Edit: Isn't the the ft to m conversion for the height wrong?

<comment><USER66> Yeah that should definitely be 2.10 meters

<comment><USER31> From the pictures, 1.10m heigth with 1.35m width looks more right; in any case, there's no simple typo:

If the feet are correct, (6.11 ft), then it should be 1.86m, not 1.10m (or 2.10m as you suggest.)

If the meters are correct (1.10m), it should be 3.61 ft (not 6.11 ft).

<comment><USER67> Wouldn't they write 6 foot 11 inches as 6.11 (eventhough it's confusing and wrong). Because that would make it 2.10 meters.

<comment><USER31> I suppose that's the most plausible explanation. (Doesn't seem to match the height-width relationship in the sketches, but its the only thing that makes the particular numbers used understandable as a fairly simple-to-explain error.)

</comment></comment></comment></comment></comment><comment><USER68> _The aerodynamic power requirements at 700 mph (1,130 kph) is around only 134 hp (100 kW) with a drag force of only 72 lbf (320 N)_

Mind blown.

<comment><USER69> But that's at a pressure of 100Pa (1/1000 atm). How much power does it take to maintain a vacuum of 1/1000atm in a tube hundreds of miles long? It seems this point is skipped over in the whitepaper, so perhaps its negligible.

Edit: yes I was referring to the power to sustain a vacuum in a leaky system, of course no power is required to maintain a vacuum in a perfectly sealed system :)

<comment><USER58> _How much power does it take to maintain a vacuum of 1 /1000atm in a tube hundreds of miles long?_

It doesn't require any power, if there are no leaks. The power required will be determined by the amount of leakage that is considered tolerable to the system.

<comment><USER70> Regular mechanical pumps can haul gas to pressures of a hPa. Any lower, and you're looking at something like turbomolecular pumps. (And efficiency may call for a second stage of specialized mechanical pumps.)

But in my experience, small mechanical leaks are usually of the order of a hPa or so, meaning no high vacuum tech will be needed. Just a fleet of giant blowers and mechanical pumps. (I worked on a wide area sputtering machine for a few years with a few hundred HP of mechanical backing pumps for about a hundred foot long chamber with a 10 sq foot average cross section (order of magnitude error for anonymity ;)) The machine would haul down to 10 or 1 hPa with leaks you could _hear_.

So yeah, it could work practically, especially if it's a welded system and not a giant mess of bolts and o-rings.

</comment></comment></comment></comment><comment><USER71> As someone who gets claustrophobic on planes - I have to fight the panic every time I fly, the dread that fills me at the thought of a service/system malfunction, while halfway between LA and SF, what happens then?

I'm reminded of this water slide at the Gold Coast's Wet and Wild - you end up going upside down - but in order to attain the velocity required to make the loop, you need to be dropped from a particular height, only some people don't make it - so they have a single access point into the tube where people who haven't made it, can get out, but I'm sure it wouldn't be a fun experience, so I opted for not going on that slide, even though my kids were pleading with me to do it. No thanks.

The hyperloop looks amazing, but my heart rate went up reading that document, and it wasn't out of excitement

<comment><USER72> If you can't stand being in an enclosed space like that, there's still the interstate. Is not meant to be everyone's ideal solution, it's meant to be a good solution for most people.

<comment><USER22> Given ADA, would it be even legal for the California government to build this instead of a classic HSR? It's not even about claustrophobics, people in wheelchairs couldn't be serviced at all and obese people would be trouble too.

<comment><USER59> I don't see why they couldn't. You could just leave out one or two rows of seats and have plenty of room for a wheelchair, also extra luggage and package (if no wheelchair was onboard). You could have that in maybe one car out of five or ten, given that a new car arrives every thirty seconds.

<comment><USER22> From the pictures it looks like able-bodied passengers don't sit upright, so a person in a wheelchair wouldn't fit. Perhaps they could be helped into a seat and then helped out, though.

Serious question BTW, I'm not sure what exactly ADA mandates.

</comment></comment></comment></comment></comment><comment><USER73> I have an anecdote here that is both funny and sad. My friend's mom visited a few years ago from Germany.

After she returned home she said that she really had enjoyed the trip, especially the trip on "the old, historical train".

She was talking about Amtrak.

</comment><comment><USER74> No toilet, and no way to get off, or even really stand up? I know some personal jets lack such facilities, but they're not exactly open to the public. At least on BART you can move away from the crazy...

<comment><USER75> No toilets on commuter buses either and people ride them 45minutes to 1+ hours everyday with no issues.

You're stuck in the "long trip" "it's like a train" framework.

It is neither.

<comment><USER76> Commuter buses stop regularly.

<comment><USER77> The commuter busses in NYC don't have bathrooms. For instance the X1 bus goes 45 minutes non-stop:

Schedule: [http://www.mta.info/nyct/bus/schedule/xpress/x001cur.pdf](http://www.mta.info/nyct/bus/schedule/xpress/x001cur.pdf)

</comment></comment></comment></comment><comment><USER78> In Brazil the building of a new high speed train between São Paulo and Rio was just delayed for the third for for lack of interested companies to build the system. The estimated cost is at US$ 17B.

There are not earthquakes in Brazil and the length should be around 500km. It seems like a better candidate than SF-LA.

just saying,

<comment><USER31> California is more able to attract interested private operators because the availability of potential passengers with money to spend on fares is substantially greater.

<comment><AUTHOR> Not sure why you think there would be more passengers on LA-SF versus SaoPaolo-Rio: Greater populations, shorter distances and lower costs ($17 vs 68 billion). Brazilians may be poorer today but they are catching up fast.

Sure there will be private contractors but is there really any private interest in building and/or operating high speed rail in CA? Perhaps Hyperloop will change things but so far it has been government led and financed.

<comment><USER31> > Not sure why you think there would be more passengers on LA-SF versus > SaoPaolo-Rio

More potential passengers in the latter, more potential passenger _revenue_ in the former.

> Brazilians may be poorer today but they are catching up fast.

Per capita GDP in Brazil is less than 1/3 of that in California, and is increasing at about 1.7%/annum (2.7% GDP growth, 0.9% population growth); assuming no growth in California GDP per capita, it would take Brazil more than 65 years to catch up.

<comment><AUTHOR> People in Sao Paolo and Rio are about 40% richer than average Brazilians which reduces the gap somewhat. And GDP growth in Brazil has averaged 3.1% since 1991 with Sao Paolo growing faster. Costs are expected to be much lower for construction ($17 vs $68B) and probably operation. Also they expect it to take 5 years to build versus 15. Not sure how it would all shake out but does not seem to be a clearly worse project.

It's probably moot comparison anyway as best I can tell the Brazil HSR is not going to happen. There have even been giant protests over transportation and government spending.

I'm also pretty skeptical that CA HSR will actually get built - numbers don't add up and popularity is declining. If they can build and operate the Bakersfield to Fresno segment on schedule and budget it might have a chance - but I have doubts they can even do this.

</comment></comment></comment></comment></comment><comment><USER79> I like how the head of the project called him to make sure he knows it's not the absolute slowest or most expensive per mile only nearly so.

</comment><comment><USER80> I'll just leave this here:

[http://jacquesmattheij.com/elon-musk-and-the- hyperloop](http://jacquesmattheij.com/elon-musk-and-the-hyperloop)

Looks like I nailed most of it. So, who is going to build a proof-of-concept scale model of this thing a few kilometers long?

<comment><USER81> Sorry - I'm afraid you were wrong on almost all, if not all, counts.

Tunnel is pressurised - wrong.

Use of the word "loop" means that something is 'recycled' \- wrong.

Parallel tracks used for acceleration - wrong.

Carriages help push each other - wrong.

Internet analogy - wrong.

Summary: scaled up pneumatic tube - wrong.

</comment></comment><comment><USER82> Some interesting tidbits:

        The total trip time is approximately half an hour, with capsules
        departing as often as every 30 seconds from each terminal and carrying 28
        people each. This gives a total of 7.4 million people each way that can be
        transported each year on Hyperloop. The total cost of Hyperloop in this
        analysis is under $6 billion USD. Amortizing this capital cost over 20 years and
        adding daily operational costs gives a total of about $20 USD (in current year
        dollars) plus operating costs per one-way ticket on the passenger Hyperloop.

        For aerodynamic efficiency, the velocity of a capsule in the Hyperloop is
        - typically: 300 mph (480 kph) where local geography necessitates a tube bend radii
          < 1.0 mile (1.6 km)
        - 760 mph (1,220 kph) where local geography allows a tube bend > 3.0
        miles (4.8 km) or where local geography permits a straight tube.

</comment><comment><USER83> A country like America in the '60s, '70s, or maybe even '80s would build this in a heartbeat.

A country like America today...who knows?

This plan has the perfect mix of reasonably practical yet slightly unsettlingly new and unfamiliar. It is just the sort of thing that meaningfully evolutionary changes are built on, like airliners or cross- country trains or steam-powered ships. If America builds this, great! If not, watch for which country _does_ and move there post-haste!

</comment><comment><USER84> "Btw, this is not the very latest version. Will post an updated version with several late arriving corrections in a few hours." [https://twitter.com/elonmusk/status/367028946426019840](https://twitter.com/elonmusk/status/367028946426019840)

</comment><comment><USER85> Cache needs busting [http://www.spacex.com/hyperloop?a=b](http://www.spacex.com/hyperloop?a=b)

nm, they fixed it

<comment><USER86> thanks! here's the actual pdf: [http://www.spacex.com/sites/spacex/files/hyperloop_alpha-201...](http://www.spacex.com/sites/spacex/files/hyperloop_alpha-20130812.pdf)

</comment></comment><comment><USER87> From my skimming of the PDF, it sounds like a pneumatic tube transportation system with a compressor fan on the front of the vehicle that moves high- pressure air from the front to the back maintaining a low-pressure state around the vehicle. Kind of like an Earth-bound Alcubierre drive.

<comment><USER88> Does it support multiple pods in the tube at once?

<comment><USER89> Yes, but no discussion of how you'd bring the system down if one broke down mid-trip or how you'd bring it back up. The individual cars only carry power to maintain speed, no to accelerate, so if they have to stop because something goes wrong, a whole bunch of people are stuck in the middle of nowhere without a toilet (or air?)

<comment><USER90> There's some discussion on pages 52-54 of the PDF.

</comment></comment></comment></comment><comment><USER91> Most fascinating likely medium-term event: The hyperloop will be built outside the US, most likely in China, after changes and development that help China claim it as primarily Chinese in design.

<comment><USER92> I agree. This is great but it won't be built in the US.

We have become risk averse. No grand sweeping visions of building interesting infrastructure like TVA, the Interstate (though that was poorly implemented in many areas), etc.

</comment></comment><comment><USER93> Australia needs to build this between Sydney and Melbourne. Plenty of sunlight to power it. Not much risk of earthquakes.

There is enough traffic to support it. [http://en.wikipedia.org/wiki/World's_busiest_passenger_air_r...](http://en.wikipedia.org/wiki/World's_busiest_passenger_air_routes)

<comment><USER94> Perth > Adelaide > Melbourne > Sydney > Brisbane would be better.

Not going to happen, but would be awesome if it did.

</comment></comment><comment><USER95> I think his vision is based on Futurama: electric cars -> spaceships -> elevated transportation tubes -> hover cars -> robots. I bet if the government still goes with the traditional rail plan, then Elon will build "his own hyperloop", adding "blackjack..." and other stuff.

</comment><comment><USER96> I thought Musk said it wasn't an evacuated tube. Does it not count because it's very low air pressure and not a completely hard vacuum?

<comment><USER97> I think it's fair that he said that. A vacuum tube has as little air as possible to help things move. His paper explicitly says it is more cost effective to have some air and his capsule design depends on air as a levitation cushion. If he had said it was a vacuum tube, no one could have guessed the levitation method.

</comment></comment><comment><USER98> "... each passenger will have access their own personal entertainment system."

Only a small point. Other than to display ghastly advertising, why not a dumb monitor that interfaces with your phone/tablet? It's not like you're going to be able to watch a movie. And if we're seven years into the future on this, I'll be wearing my Oculus Rift 4.0 anyway.

Maybe I'm just too disillusioned by the systems used in aircrafts with their awful interfaces, lag, etc.

</comment><comment><USER99> Best comment on reddit so far "this is a pipe dream"

* I don't think the Hyperloop is viable and I hope they kill the $100B High Speed Rail (HSR) project before it ruins the SF Peninsula and budgets across the state.

* Setting aside the $100B HSR cost (yes, I know current estimates are $70B but it was sold at $10B and will easily exceed $100B if/when completed) the operating costs will have to be subsidized for every minute of its existence just like every other govt boondoggle. This is a white elephant and, in case you weren't paying attention, California and most cites are or soon will be bankrupt. We can't afford this, cut our losses now.

* If I was made Bay Area/CA public transportation csar (with suitable budget and dictatorial powers) my first step would be to extend BART through San Jose so it actually loops the bay and (finally) complete BART. (I am old enough to recall that that was the original design)

* I do think a high speed rail connection SF/LA is economically viable but would need to do research and crunch numbers while finishing BART. I would move the SJC airport south (with a BART extension) to Morgan Hill/South San Jose and build the connection from there to LA.

* From SJ to LA I would confiscate I5, leave two lanes for truckers and local traffic but build a high speed (300MPH) car/ferry train system so you could be blasted to LA in a little over an hour and have your car there when you arrive. Home by dinner.

* I would build a nuclear plant somewhere halfway between LA and SF on I5 so my trains would not have to use diesel fuel (too smoggy) or solar (too expensive).

Nothing here is any less fanciful than Musk's musings and far, far more practical.

</comment><comment><USER100> From the conference call: "I'm tempted to at least make a demonstration prototype, but I think I would have to punt it for a little bit of time, it wouldn't be immediate."

Source: [http://live.theverge.com/live-hyperloop-announcement-elon- mu...](http://live.theverge.com/live-hyperloop-announcement-elon-musk/)

<comment><USER101> Heres another live blogging source [http://gizmodo.com/our-hyperloop-liveblog- starts-right-here-...](http://gizmodo.com/our-hyperloop-liveblog-starts-right- here-at-5-pm-et-2pm-1110567755)

</comment></comment><comment><USER102> _The total cost of the Hyperloop passenger transportation system as outlined is less than $6 billion USD (Table 8). The passenger plus vehicle version of Hyperloop is including both passenger and cargo capsules and the total cost is outlined as $7.5 billion USD (Table 9)._

Love the idea but the cost projections here seem extremely optimistic.

</comment><comment><USER103> I love the fact that Musk is publishing this publicly preemptively blocking future patent claims on the basis of prior art.

</comment><comment><USER104> I have somewhere read, that large cities are usually the size one can travel in under an hour. So this could have quite interesting effects in effectively joining LA and SF.

<comment><USER105> San Angeles?

</comment></comment><comment><USER106> "Btw, this is not the very latest version. Will post an updated version with several late arriving corrections in a few hours." [https://twitter.com/elonmusk/status/367028946426019840](https://twitter.com/elonmusk/status/367028946426019840)

</comment><comment><USER107> I see just a little bit of hand-waving with how to deal with the 300 psi and 1000 degree F air.

He says they will cool it with on-board water and storing the steam (I don't see a pressure here)in the vehicle. Given the tight space, will any kind of thermal insulation breakthrough be needed?

<comment><USER104> Probably not, the pressure and thus the density of the air is really low and therefore it simply does not have the energy density needed to cause problems.

<comment><USER107> The almost vacuum at the front of the pod is compressed and piped out the back and to the air bearings. After it is compressed it is 1000 deg. F and 300 psi. That sounds pretty energetic to me

</comment></comment></comment><comment><USER108> Thought this was amazing: $20 for a one-way, 35 minute trip from SF to LA.

<comment><USER109> Well it has to beat a standard commuter car (~$45 one way@34mpg) by a significant margin to be useful for consumers.

What about freight?

<comment><USER110> Time is money too. The drive from SF to LA is about 5.5 hours (per Google Maps). 5.5 hours of stress and frustration, compared to 30-40 minutes of hyperloop...

<comment><USER111> Just as an anecdote.. We had some friends from Orange County come visit us in SF this past weekend.

* OC -> SF -- Left at 3pm, took 9.5hrs to drive * SF -> OC -- Left at 9pm, took 7 hours to drive

There is random night construction as well as detours and traffic to worry about on I-5. Half an hour would be a no-brainer, even if it only went so far as downtown LA.

</comment></comment></comment></comment><comment><USER112> Seems like this would be particularly vulnerable to terrorist attacks. There is a huge surface area that needs to be protected (tubes/pylons). If there are pods leaving every thirty seconds and traveling at supersonic speeds then taking out one pylon could kill several hundred people and leave the entire train inoperable. In a future where this design was used extensively to connect cities on the coasts it would quickly become a critical piece of transportation infrastructure. Attacking several arcs of the city graph simultaneously would be utterly debilitating. Especially if the system's relative efficiency leads to the displacement of other forms of transportation.

<comment><USER113> Nope. Read the document. Subsonic speeds with capsules 2 minutes apart. In the event of a catastrophic depressurization (i.e. bomb on a capsule or a pylon), all capsules stop. Worst case, 28 people in one capsule die. The rest are stuck for awhile until they can be evacuated. Not very spectacular.

<comment><USER112> Wow excellent. I didn't read the whole document thanks for being thorough.

</comment></comment></comment><comment><USER114> _Feedback is welcomed on these or any useful aspects of the Hyperloop design. E-mail feedback to email@example.com or firstname.lastname@example.com_

Better:

[https://github.com/hyperloop/hyperloop](https://github.com/hyperloop/hyperloop)

<comment><USER115> "Open source" plans in PDF format. "But we published it on github, that makes it open source, right?"

RMS is rolling over in his -- oh wait, he's still alive.

How about a ReST or LaTeX document that generates this PDF?

<comment><USER116> It's not the paper that's open source, it's the information...

</comment></comment></comment><comment><USER117> > Risk of derailment is also not to be taken lightly, as demonstrated by > several recent fatal train accidents.

Interesting. No comment on the potential outcome of a passenger-filled capsule being ejected from a burst tube on high pylons at 350mph.

<comment><USER118> Also, I wonder what HSR incidents he's referring to. The Spanish relatively low-speed human error crash? Systems like Japan's Shinkansen have never had a fatal accident, despite operating at the edge of technology for 50 years. I don't think a derailing accident is at all likely on a modern system like California's plan or the UK's HS2.

<comment><USER119> Check out Eschede.

</comment></comment></comment><comment><USER120> Wow. I was expecting it to be something like the UW Ram Accelerator (RAMAC), but he put a fan in front. I was thinking it would have natural gas/detonation for propulsion, using the ram jet principle, and continuous acceleration, but I guess that rapidly gets you to totally absurd speeds (10km/sec+) and wouldn't really be viable, plus humans aren't so into 10G+ acceleration even when mounted laterally.

I would totally ride this. I hope there's a way for California to build it, and more importantly, I hope we can fix our government somehow to allow projects like this to actually happen in multiple fields.

</comment><comment><USER121> The pressure difference is higher than in a passenger jet. The pressure vessel must be a tubular structure with small well sealed doors. None of this prism with whole fuselage gull wing door stuff.

</comment><comment><USER122> So who wants to start a company? I'll uh...come up with the business plan.

Seriously though, this would be an incredible project to work on. I wonder, outside of Elon Musk, who would take on the challenge?

<comment><USER98> Might Tony Hsieh champion a group pushing for LA to Vegas? I imagine SF-Vegas might have a roundabout route.

<comment><USER122> That could definitely make sense. Vegas might even put up some capital to make it easier for people to visit and put their hard earned dollars to good use.

I can also imagine that from an infrastructure standpoint building across desert you'd run into fewer obstacles, although that might be wishful / oversimplified thinking.

<comment><USER98> And 30 minutes would mean that you could go to Vegas on a Friday or Saturday night and return to crash in your own place.

</comment></comment></comment></comment><comment><USER123> So one question that hasn't really been mentioned yet... What happens in the event of a fire?

Do you just keep going? Stop the Fire suppression systems?

Given any worst-case scenario.. how do you escape from the tunnel?

<comment><USER124> Or what if it breaks down and you're stuck in the middle of nowhere. How do emergency vehicles reach the pod if it is disabled in a sealed tube?

</comment></comment><comment><USER125> None of this is to say that Hyperloop is a bad idea. The idea sounds very interesting and I'd rather spend sixty billion building a Hyperloop --even if it fails-- than the ridiculous California high speed rail project.

Cost is probably off by an order of magnitude, if not more. Why? Unions and other groups. Building anything in this country costs massively more (and takes significantly longer) than one could imagine because of our unions are not business symbiotic. The goal of union leadership is to extract as much as they can out of the businesses they infect, even if this means their demise.

A lot of the unions that would be part of such a project have some of the laziest and most problematic people working for them. If you come from the Silicon Valley tech world my words make no sense to you. In fact, you might think I am nuts. All I have to say is: Do a good size trade show exhibit at a few of the unionized convention centers in the US and then see what you think about US unions. Then repeat that experience at various locations in Europe and Japan and see the difference. I have done just that. US labor unions are destroying our country from the inside out.

How many significant new civil engineering projects in the US can you name over the last, say, fifty years. Right.

Hyperloop cost would be way more than this paper seems to predict.

The political factor is grossly underestimated. Our reality is that we live at a time of political deadlock. Nobody can or wants to make a decision and the decisions we do make tend to be suboptimal, sometimes grotesquely so: example, California high speed rail.

Finally, it addresses the wrong market. I am not sure why people insist on applying trains to transporting people in the US. Sorry to resort to reality folks: If you build it they will NOT come. We do not have that culture and you will not inspire it simply by building trains. You'd have to forcefully push people in that direction through legislation that would make it too expensive to not use rail. In other words you'd have to declare war against other methods of transportation through punitive actions.

The right place for high speed rail in the US is cargo, not passenger rail. If we could evolve our cargo rail systems to move at 300 km/hr rather than 50 the consequences would provide economic benefits and development beyond a century.

The final point is related to politics. We have a decision making system that allows anyone to vote. And, while this is commendable, it does create horrible problems. Imagine allowing a random group of, say, ten people deciding whether or not your child should have surgery. I'd be surprised if anyone thought this to be a good idea. No, most people would rather have a group of experts in the field, more than likely MD's in this case, vote for such a decision. The ridiculous California high speed rail project is a result of hordes of low- information, mathematically challenged, technologically ignorant and financially ignorant voters being led by the nose by unions, media and political forces.

How do you move forward when people like that can vote on these issues and their vote has equal value to that of an expert in the relevant fields: a PhD in Physics, an engineer, a financial expert, etc.

Regrettably this is not a technological problem. It is far more complex than that.

<comment><USER21> I'm with you that Musk seems to have ignored the human factor when estimating the cost or even the feasibility of the project.

But think about how many aspects of our lives it would revolutionize. Simple example: can you imagine what would happen to the SF real estate market if it suddenly had to compete with the LA real estate market? If talented people who live in LA could suddenly commute to and from companies in SF?

And that's just real estate.

<comment><USER124> I would say any stop in between the two cities would have a large spike in growth, as they suddenly become viable commuter communities, much like how suburban towns on the east coast grew out of proximity to regional rail lines. Suddenly a little rural truck stop town like Lost Hills becomes a viable commuting suburb.

<comment><USER125> That's probably true. I could see far more impact in places like that, say, Santa Monica or Irvine.

</comment></comment></comment></comment><comment><USER24> Note that the UK's new high speed rail (HS2) is budgeted at £33bn ($51bn) and likely to exceed that[0]. Being mostly straight, and across land already approved for rail use, it seems like an ideal candidate for a hyperloop alternative.

At 120 miles long[1] compared to the SF<->LA ~350 miles, a UK hyperloop would be even cheaper, especially since the major cost is the tube itself. A back of the envelope calculation[2] gives a cost of about £1.9bn ($2.9bn) which is suspiciously, almost absurdly, cheap.

If anyone can find any flaws in this argument (specifically related to e.g. UK-specific issues/laws that I may be unaware of) I'd be very interested to hear them!

[0] [http://www.independent.co.uk/news/uk/home-news/revealed- hs2s...](http://www.independent.co.uk/news/uk/home-news/revealed-hs2s-33bn- budget-already-derailed-before-a-track-is-laid-8527920.html) [1] [http://en.wikipedia.org/wiki/HS2](http://en.wikipedia.org/wiki/HS2) [2] using average cost values from the pdf, not accounting for differences in pylon height/amount of tunnel required etc.

<comment><USER126> The two biggest budgeted costs in the latest report I can find (£16B) are stations (£1.7B) and tunnels (£1.4B). (Also noteworthy is that almost £10B of the overall £16B figure is for risk provision.) More directly comparable is the £1B figure for land acquisition: that isn't going to fall by much.

</comment></comment><comment><USER127> A wonderful proposal and inspiring: I think the air bearing, partially evacuated tube and axial flow compressor powered by onboard battery are an innovative combination worth exploring, and I am sure with the correct leadership and political will could produce a really useful enhancement of transport infrastruture. However on reading many of the comments bemoaning current state of construction in the US, as well as unions and vested interests; had to provide this quote of Machiavelli's: It ought to be remembered that there is nothing more difficult to take in hand, more perilous to conduct, or more uncertain in its success, than to take the lead in the introduction of a new order of things. Because the innovator has for enemies all those who have done well under the old conditions, and lukewarm defenders in those who may do well under the new. This coolness arises partly from fear of the opponents, who have the laws on their side, and partly from the incredulity of men, who do not readily believe in new things until they have had a long experience of them.

</comment><comment><USER128> Holy hell

A 57 page document

I expected mostly fluff.

<comment><USER129> To me those sentences don't really fit together. 57 pages is a lot so let's hope it actually is not mostly fluff. I won't read that so I would be much happier with a 100 word tldr.

<comment><USER130> Personally, I'd prefer a video explaining this to the layman.

<comment><USER131> The first few pages are an explanation in layman's terms.

<comment><USER129> thanks, you made me download it :)

</comment></comment></comment></comment></comment><comment><USER132> Interesting that Charles Alexander's writeup was said by Musk to be the most similar, when the ideas were fairly dissimilar by the end.[1]

[http://charlesalexander2013.wordpress.com/2013/07/18/hyperlo...](http://charlesalexander2013.wordpress.com/2013/07/18/hyperloop- riding-sounds-density-peak-to-exploit-the-drag-equation/)

</comment><comment><USER133> James Bond used Hyperloop prototype, a modified pig, in "Living Daylights" back in 1987. [http://www.youtube.com/watch?v=-AzJ5_8Cqdc](http://www.youtube.com/watch?v=-AzJ5_8Cqdc) [http://en.wikipedia.org/wiki/Pigging](http://en.wikipedia.org/wiki/Pigging)

</comment><comment><USER134> I just posted a link to the Hyperloop spec, written as a "tree document"... Makes it easier to quickly absorb the main points.

[https://news.ycombinator.com/newest](https://news.ycombinator.com/newest) [http://gingkoapp.com/hyperloop](http://gingkoapp.com/hyperloop)

</comment><comment><USER135> I'm impressed, but I'm afraid Hyperloop's operation is modeled after airplanes, while the actual use of the system would be closer to a city bus.

>All capsules would have direct radio contact with station operators in case of emergencies, allowing passengers to report any incident, to request help and to receive assistance. In addition, all capsules would be fitted with first aid equipment

>Typical times between an emergency and access to a physician should be shorter than if an incident happened during airplane takeoff. In the case of the airplane, the route would need to be adjusted, other planes rerouted, runways cleared, airplane landed, taxi to a gate, and doors opened. An emergency in a Hyperloop capsule simply requires the system to complete the planned journey and meet emergency personnel at the destination.

What happens if a brawl erupts inside a capsule? What happens if a suicide bomber boards the Hyperloop?

<comment><USER136> What happens if a brawl erupts inside a moving bus or taxi?

What happens if a suicide bomber boards a train or bus?

What happens if a suicide bomber rents a car and crashes it into you as you walk along the sidewalk?

Rather than living in perpetual fear, you could try making the world a place where people who can't get food or work aren't trying to blow you up as a last resort?

Americans seem to be the most worried about suicide bombings out of anybody else, yet America has probably seen the least suicide bombings per capita of any country in the world. (yes, exaggeration)

<comment><USER137> _Americans seem to be the most worried about suicide bombings out of anybody else, yet America has probably seen the least suicide bombings per capita of any country in the world._

Not that I approve of many of the things we do to "prevent" them, but...

Perhaps worrying about preventing certain things sometimes actually helps reduce them?

<comment><USER136> I'd agree in some cases, but realistically there isn't much you can do against people using bombs to blow up bridges - or in this case, hyperloop pylons. It's just not something that you can 'design around'. Designing the pylons to survive if one is blown up? If someone can put a bomb on one pylon, he can put 5 bombs on 5 pylons. Or under 5 cars.

Spending your time trying to prevent that kind of thing is futile and an enormous waste of resources. See: TSA

</comment></comment></comment></comment><comment><USER138> ... could CHSRA just build this? I understand they're in the planning stages, and I don't think it'd be absurd to say "this is a train, just better and cheaper".

Edited to add: My question was primarily legal - if someone were to step up and demonstrate this was feasible could it possibly make a difference?

<comment><USER31> > could CHSRA just build this?

No.

> I understand they're in the planning stages, and I don't think it'd be > absurd to say "this is a train, just better and cheaper".

This is a hypothetical concept, while HSR is a widely demonstrated, well- established technology, with real vendors with proven situations. There's a lot of _civil_ engineering to go into building the infrastructure, but the _technology_ is there (and isn't still looking forward to "[s]ub-scale testing based on a further optimized design to demonstrate the physics", as is the case with hyperloop.)

Hyperloop as an alternative to HSR is about in the same situation as nuclear fusion as an alternative to wind (or nuclear fission) power. .

</comment></comment><comment><USER139> I'm pretty sure the first Hyperloop will be built in China.

</comment><comment><USER140> So, it's a two-lane highway where the cars are 5 miles apart? How many people will be able to use this thing?

<comment><USER141> From the report: "...with capsules departing as often as every 30 seconds from each terminal and carrying 28 people each. This gives a total of 7.4 million people each way that can be transported each year on Hyperloop."

<comment><USER142> Eventually hits up against this problem:

[http://books.google.com/books?id=DenWKRgqzWMC&pg=PA67&lpg=PA...](http://books.google.com/books?id=DenWKRgqzWMC&pg=PA67&lpg=PA67&dq=schelling+ski+lift&source=bl&ots=dMjA9zdq94&sig=0Chc- xZxKhla1GMrY0AGEd_2GAQ&hl=en&sa=X&ei=i1QJUpTBFOL0yQH60YGIDg&ved=0CC0Q6AEwAA#v=onepage&q=schelling%20ski%20lift&f=false)

<comment><USER143> Ehh, really you don't just speed up the lift you redesign the whole loading and unloading system to allow it to load and unload more people per second. You see this in actual high speed lifts.

<comment><USER144> > You see this in actual high speed lifts.

Except that the chairs on a high speed lift have to be so much further apart, so you're not actually getting more people to the top in the same unit of time.

Source: I'm an Engineer and worked on fixed grip (slow) and detachable (fast) chairs and gondolas for 5 seasons.

</comment></comment></comment></comment></comment><comment><USER145> It's very interesting that this is a SpaceX project. Why not Tesla, or another company entirely?

<comment><USER146> This is not going to happen. It is a very rich, successful engineer musing at what might be possible if we thought radically different about transportation. I'm as big a fan of Elon Musk's projects as anyone, but the weight assigned to these napkin calculations is ridiculous.

[Edit: If anything, this might lead people to take this type of eccentric and radical design more seriously. But given the criticism Musk's engineering ventures have had before, I wouldn't count on it.]

<comment><USER147> I hope this happens. I've only started reading the .pdf and cannot claim I will understand everything but it seems like a very promising read. If Musk can partner with Richard Branson and other billionaires (along with contributions from people on the web) it could happen!

</comment></comment></comment><comment><USER148> I think you should improve rail network in overall than work on this crazy idea. Anyway good luck.

</comment><comment><USER149> I like the idea of transporting cars with passengers or just cars/SUVs. That would be ideal. Travel from point a to point b like a ferry. Or extension of our current super highway network. Use your personal transport machine after arrival. In most of the USA when traveling outside the dense urban areas driving a automobile is the preferred form of transportation. It would make the world a smaller place much like how cars and paved roads did 100 years ago. If we could hyper transport our vehicles at large chunks of distances say 300+ mile integers. I could only imagine this future.

Freight shipping would greatly benefit. Build a freight tube only across the US mainland. Amazon Prime? Same day delivery.

<comment><USER150> It's actually really stupid. Car sharing models mean you'll have a car waiting for you at the destination. There's no reason to bring your own steel and rubber.

<comment><USER149> What is Car sharing models ? It's simple and could be the best use of this technology. Make all the US superhighways major and key corridor stretches hyperloop. Enabling you as a driver to get around the country faster saving energy and time.

</comment></comment></comment><comment><USER151> Did anybody ever see Discovery Channel's Extreme Engineering episode about a possible high speed train from London, UK to NYC, USA?

[http://www.smartplanet.com/blog/intelligent-energy/new- york-...](http://www.smartplanet.com/blog/intelligent-energy/new-york-to- london-in-an-hour-by-train/16456)

[http://www.youtube.com/watch?v=frYWTrEfPRs](http://www.youtube.com/watch?v=frYWTrEfPRs)

This reminds me a lot of that, but without the vacuum tunnel... there was a proposal in 1960's apparently... so no so new after all.

[http://en.wikipedia.org/wiki/Transatlantic_tunnel](http://en.wikipedia.org/wiki/Transatlantic_tunnel)

</comment><comment><USER152> Aside from the whole "will they actually build it" debate, I'm worried that if they do, the capsule ceiling won't be high enough for someone fairly tall (let's say 6'5'' or taller) to sit in comfortably. I'd assume the height of the capsule will have some effect on the drag involved, as well as the necessary size of the tube, so it makes sense to make it as short as possible.

Musk himself stands just below 6', so he may not naturally think of us taller folk. I'd hate to have to slouch for the trip, even if it is only projected to be 35 minutes.

edit: dear tall people who have ridden in one of Tesla's cars: how's the headroom in a Model S?

<comment><USER6> Re. headroom in Model S: [http://www.teslamotorsclub.com/showthread.php/10879-Any- tall...](http://www.teslamotorsclub.com/showthread.php/10879-Any-tall-Model-S- owners-yet)

</comment></comment><comment><USER94> Originally I thought it was going to be inside a transparent tube that you could see out of - one of the only downsides to this is that you are inside a steel tube with no view. Technically not important, but may be important for some passengers.

</comment><comment><USER153> OK, so he says it's much cheaper than high-speed rail mostly because pylons require taking much less land through eminent domain. Can anyone explain to me then why high speed rail can't be built on pylons?

<comment><USER154> Weight of the rolling stock.

<comment><USER153> "For those who don't know the lingo, "rolling stock" just means "all the vehicles on the train."

Does he say this explicitly? (Sorry if I missed it.) Why can't you make a train car just as light as these cars, and also skip the weight of the tube?

<comment><USER121> Probably regulations. They have to maintain integrity in collisions. I don't know if they have to take into account having very heavy freight trains on the same tracks as well.

<comment><USER155> Train regulations are retarded in the US and haven't been reformed for over 50 years. Basically if you plan on having a crossing or sharing track with a freight train you automatically are stuck with the FRA regulations which apply to freight trains and are also pointless. Those regulations require absurd rigidity of rolling stock to the point that train-sets built for those specifications actually are more expensive to maintain, fail more often simply (rolling stock becomes too heavy), and are much more unsafe.

For example FRA requires train rolling stock to withstand 800,000lbs of force on impact without permanent damage. The European requirement on the other hand is less than half of that. The European requirements instead aim for adding "crumple zones" to the cars to absorb energy and protect occupants similar to how automobiles use crumple zones.

This is why there's an obsession in the USA regarding light-rail. Light-rail sidesteps the FRA regulations by creating a separate track and rolling stock that doesn't have crossing with heavy rail.

I believe if we simply reformed FRA regulations we could probably cut all rail development by a sizable chunk as we would be able to buy rolling stock as-is from European and Asian suppliers.

But anyway, back to the point being discussed. A sizable chunk of China's HSR network was built elevated so it is certainly feasible to put today's HSR tech on pylons. But just because you elevate something doesn't magically get you away from Environmental Reviews which I think is another area where a majority of the cost in public works project lies.

Environmental reviews will still be required for Hyperloop. Since it is actually a _new_ system, I would expect it to get even more scrutiny in the public eye because it will sound even more magical and also offend even more people since there won't be any intermediate stops. Remember that much of the California HSR political issues are because central valley cities and towns _want_ an HSR station in their town (of course they don't want to fund the station). So many of these towns basically come to the table and say "we'll give you the land if you give us a station, otherwise we won't help you." The Hyperloop concept basically ignores this argument.

Keep in mind that despite environmental reviews having the word "environment" in them, they are actually also public hearings where the public can voice their opinions which can include things like additional noise and traffic. For example if your project blocks out the beach view of a home-owner's house overlooking the ocean, you can sure bet that they'll be at the environmental review and give you an earful about how you can't build your tube/track/freeway/skyscraper/windmill there. Yes that's a bit of hyperbole but that's basically how the environmental review phase is abused.

Because of that, I've come to the conclusion that we won't have any significant improvement in infrastructure in this country until CEQA/NEPA are reformed to allow not just public entities to build infrastructure, but also private entities as well.

</comment></comment></comment></comment></comment><comment><USER156> Sorry, but I do not believe this will be cheaper than conventional rail. This is essentially a vacuum tunnel. Ok it is not a perfect vacuum but it is still supposed to keep 1/1000th of the earth's pressure.* Keeping such a vacuum over several hundred miles of metal tubing would be very very expensive.

This may work but it will be several times more expensive than the HSR system.

* Oh and by the way, it is completely misleading and annoying for musk to refer to this as merely 1/6th of Mars's pressure. That would be a really relevant statistic if he was building his thing on mars.

<comment><USER157> Would it really be expensive? 1 mbar is a low grade vacuum. You can achieve that with mere rotary vane pumps:

[http://en.wikipedia.org/wiki/Rotary_vane_pump](http://en.wikipedia.org/wiki/Rotary_vane_pump)

</comment></comment><comment><USER158> Just finished reading the pdf and now I understand why this is by far the most popular HN post for a long time (ever?). I now post my feeble comment to be lost in a sea of enamored nerd buzz.

Fucking awesome, Elon.

<comment><USER159> Can you explain? I'm at job and don't have that many time to read whole PDF.

<comment><USER158> Just read the first part, it's only a few pages.

It's an exciting approach to high-speed land travel at a proposed cost of far far less than the California coastal rail's $70 billion minimum price point.

</comment></comment></comment><comment><USER160> [http://www.spacex.com/sites/spacex/files/hyperloop_alpha-201...](http://www.spacex.com/sites/spacex/files/hyperloop_alpha-20130812.pdf)

</comment><comment><USER161> From a telecommunications stand point, we were just starting to get handovers to work on high speed rail, now we have to get it to work on super sonic transport? come on now :D

</comment><comment><USER162> I'm really curious about turns and switches. The latter more about loading and unloading. If you have a platform to carry 300 people / hr to or from the other city how do you load them and keep them organized.

The failure scenarios are interesting too. Lets say a tube breaks, if the linear motors are spaced out, how do they brake? Turn off the air lift? Does that then destroy the tube they are in? What is the emergency exit like?

</comment><comment><USER163> God damn it, Elon! It looks amazing but the logistics are just not adding up! 2-minute departure time scales? Good luck getting the future Hyperloop TSA to do that.

But, the numbers don't quite crunch for this to be a legitimate business (unless we are talking no returns for 25 years charging customers an average of 1500-3000 dollars per ride .. but the demand is not there for those prices).

Idea is awesome .. yes! Viable ... yes, yes!! A business ... idk. :(

<comment><USER164> Planes take off from runways every minute or two.

Vehicle loading and unloading terminals can fan out from the automated system that loads them and unloads them from the actual Tube.

</comment></comment><comment><USER165> Does anybody else wonder how easily the rotor will slot into the stator at 700 MPH? It looks like pretty small tolerances. Maybe guide rails leading up to it?

<comment><USER166> I'll believe anything now I've seen the videos documenting the Talgo variable- gauge system. Also, the tolerances in terms of distance from track of the Transrapid maglev are pretty good. I wouldn't be surprised if you can fly an air-cushioned vehicle with similar precision.

</comment></comment><comment><USER167> Made me think of a scifi book I read recently where terrorists attacked the hyper-speed rail system by leaving a bowling ball on the "tracks"...

</comment><comment><USER168> "by placing solar panels on top of the tube, the Hyperloop can generate far in excess of the energy needed to operate."

He seems to be planning to build this over farmland? Because farmers aren't going to be happy about someone blocking their light.

Light is the limiting factor in plant growth.

If he's going to block the light to farms he'll have to pay them for the lost crops, and then he might as well just buy the land.

<comment><USER169> I've driven from LA to SF and back along I-5 a few times, I recall lots of cattle farms, I don't recall ass much agriculture (though their definitely was some).

At the same time, the aquaduct runs along I-5 for a considerable length. I think building along the aquaduct would make a lot of sense. I'm assuming that land is already owned by the gov't, and is already somewhat protected along it's length.

<comment><USER168> I couldn't find the aquaduct on google maps, but I do see lots of "brown" land, so I guess it's not as heavily farmed as I thought. Not enough water presumably?

</comment></comment></comment><comment><USER170> So, a sealed tube from A to Z, passing B through Y. No benefit to B through Y at all. So why do B through Y allow the tube to pass through?

When railways happened, B through Y believed they would see economic benefit, and often did. They got a station. Not so here, correct?

There for, wouldn't this need a government to force it through? How would that happen in the USA?

To me this is where the idea runs in to the buffers, as it were.

<comment><USER171> > No benefit to B through Y at all. So why do B through Y allow the tube to > pass through?

Easy. You pay them.

<comment><USER170> Easy? Think it through.....

Who? How much? All the same? When?

Then imagine all the people from B to Y who see an opportunity to screw the project for huge amounts of cash. Decades of lawyers arguing in court over every conceivable point, or opportunity.

And that before environmental, and god know what else, groups get involved.

Sorry, no, not easy at all. Not even slightly.

<comment><USER171> The high speed rail wasn't going to stop at B through Y anyway, and the hyperloop supposedly takes less space.

<comment><USER31> > The high speed rail wasn't going to stop at B through Y anyway

Untrue [1].

[1] [http://www.hsr.ca.gov/docs/newsroom/fact%20sheets/High- Speed...](http://www.hsr.ca.gov/docs/newsroom/fact%20sheets/High- Speed%20Rail%20Big%20Picture.pdf) \- all but the "Northern California Unified Service" and "Amtrak Surfliner" runs are planned HSR lines/stations, and all (including those) are getting upgrades/improvements or new rail/connections as part of the HSR project.

</comment></comment></comment></comment></comment><comment><USER172> Really interesting proposal. How do you maintain the tube when something needs repair? You need to shut the whole system down, don't you?

<comment><USER173> Fair question. I would build 3 tubes instead of 2. That would help with repairs as well as with handling asymmetry in demand (for example, if more people want SFO->LA in mornings and LA->SFO in evenings)

<comment><USER172> I was thinking the same thing. Eat the up-front build costs, but assure yourself a persistently-functional loop. Probably the type of thing best determined as part of the review-process, and not listed a requirement in the technical draft.

</comment></comment></comment><comment><USER174> I'm curious how well this thing can "maintain distance between the capsule and tube walls". It seems like this is a much tougher problem than simply levitating the whole thing off the ground where the forces are relatively stationary. It also doesn't look like any of the artist renderings address this, and only consider the airflow lifting the thing off the ground.

</comment><comment><USER175> Why not go ahead and build the Hyperloop, and when CA HSR gets around to actually building the links into downtown LA and SF, design them to connect up to the Hyperloop, which will surely be complete and running by the time HSR is projected to be available. The Hyperloop can even share some rights of way with HSR. Why not have both?

Hyperloop should be an AND proposition to HSR, not an either/or.

</comment><comment><USER176> I don't know where he got his stats, but the energy per passenger for a train cannot be right. CSX advertises daily they can move a ton of freight 400 miles for a dollar. A person weighs much less than a ton. Granted there are additional expenses to make a human comfortable, but these are relatively low fixed costs --you know like a chair.

</comment><comment><USER177> It's now up on [http://www.spacex.com/hyperloop](http://www.spacex.com/hyperloop)

</comment><comment><USER178> I thought it was just a few days ago that elon musk said that he "wished he had never mentioned the hyperloop as he doesn't have enough time to work on it" [sic].

When I heard the news about this announcement on the radio today, I thought that my local news station was just a week behind the times as usual. Apparently they were not?

<comment><USER74> Just FYI, [sic] is used when you're quoting something with a mistake and you wish to indicate that mistake is in the source document, and not added unintentionally.

</comment></comment><comment><USER179> One part that's not getting nearly enough press: you can bring your car with you!

This is the key that will drive massive adoption. Wrote about this here:

"Hyperloop = Warp Speed for Your Car" [https://medium.com/hello- hyperloop/82cb2069112f](https://medium.com/hello-hyperloop/82cb2069112f)

</comment><comment><USER180> Could it be that Musk got some of his inspiration from the (stalled) Swissmetro project in Switzerland?

[http://www.swissmetro.ch/en/content/technology](http://www.swissmetro.ch/en/content/technology)

Same idea, different technology. Anyway, implementation is important, not the idea itself.

</comment><comment><USER181> A few thoughts:

1) We don't have to hit the ball out of the park on our first time out. I'd be happy to see a hyperloop prototype from, say, Manhattan to JFK built.

2) Which countries might "race" to get something like this sorted out (which may compel a more world-wide movement)? China? Spain? Japan?

</comment><comment><USER182> For all of you whose panties get wet at the sound of Elon Musk's name Hyperloop is essentially just Aérotrain in a tube:

[https://en.wikipedia.org/wiki/A%C3%A9rotrain](https://en.wikipedia.org/wiki/A%C3%A9rotrain)

This guy isn't really a genius, he's just rich.

<comment><USER183> Not really. There are similarities in the car's design, just as there are similarities among airplanes.

Aérotrain is a magnetic levitation train, Hyperloop does not use magnetic levitation. Read the PDF.

<comment><USER184> Aérotrain is not magnetic, it uses air resistance too. Read the link, ahem.

</comment></comment></comment><comment><USER185> I honestly expected better work. I feel like this is something everyday users on Reddit or HN could have put together in a report. I only gave it a look because Elon Musk's name is on it. That says something sad about me when it comes to the Big Imagination projects :-/

<comment><USER41> Part of what has made Musk so special is that he gets things done. As they say, ideas are a dime a dozen - what matters is execution and Musk has proven time and again that he can nail execution.

It's the same reason that pg & YC say that they really care about the founding team and frequently encourage the founders to pivot far away from their original ideas.

<comment><USER31> > Part of what has made Musk so special is that he gets things done.

Not applicable to Hyperloop, which he has pretty clearly said he is not going to get done.

<comment><USER186> > Not applicable to Hyperloop, which he has pretty clearly said he is not > going to get done.

But he conceived the idea. Ideas have value and can be said to be "done". To argue that pure ideas have no substance is to argue against science.

I think it's admirable that he published the idea without attachment or limitation, in such a way that others can turn it into hardware.

</comment></comment></comment></comment><comment><USER187> "In addition, safety emergency exits and pressurization will be added in key locations.." How could anyone predict what 'key' locations an emergency is going to happen at? And how would eviction happen, given the tube's low pressure?

</comment><comment><USER188> > Hyperloop is considered an open source transportation concept.

I'm glad they didn't just let the idea die on a drawing board somewhere because of a lack of time/money. Now, someone has to just develop it faster than someone else can legislate against it.

<comment><USER189> Given the sort of heavy infrastructure required and their related permits, I'd assume that whoever actually starts an effort to build a HL-like system, will have local politicians on board.

<comment><USER39> These days, politicians have to stay bought. And any competitor or detractor can derail your effort by buying off one of the local politicos.

This is one of the biggest reasons northern CA doesn't already have a bunch of such systems already in place.

</comment></comment></comment><comment><USER190> So ... it's a series of tubes?

<comment><USER6> ROFLMAO

</comment></comment><comment><USER191> Great KickStarter project! I'm only half kidding. Public source, why not crowd funding?

</comment><comment><USER192> I would dedicate 6-10 years getting something like this off the ground. Unfortunately I don't think anyone without the political and financial connections could pull this off. Musk could probably do it because of Musk Mania. But few others.

</comment><comment><USER193> Pretty but absurd.

With all that money I rather give a Cessna to 1M people so they can fly anywhere without restriction.

Or make special small airports for direct flight between cities. Much less infrastructure.

Kudos to Elon, I love they guy and his incredibly visionary mind.

<comment><USER59> "I rather give a Cessna to 1M people"

The average driver can't control a vehicle safely in two dimensions, much less three. :-)

</comment></comment><comment><USER194> How about some physics about this? Here is some...

[http://dmitry.gr/index.php?r=06.%20Thoughts&proj=01.%20Hyper...](http://dmitry.gr/index.php?r=06.%20Thoughts&proj=01.%20Hyperloop)

<comment><USER94> I think it mentioned in the PDF that speeds would be reduced significantly while in or near residential areas?

</comment></comment><comment><USER195> I wonder if that $70 billion price tag is partly tied to the "I created x many jobs in my time as a politician" rhetoric. I'm just assuming high cost means a higher number of people being paid.

</comment><comment><USER97> It's nice that it doesn't have drivers. As someone who visits the SF area a lot, the BART drivers strike way too much and have to be replaced by automated trains. So this is a nice step forward.

<comment><USER196> They go on strike circa every 20 years [1]. I guess you could call that "way too much", but that seems hyperbolic to me.

[1] [http://en.wikipedia.org/wiki/History_of_the_Bay_Area_Rapid_T...](http://en.wikipedia.org/wiki/History_of_the_Bay_Area_Rapid_Transit#Operation)

</comment></comment><comment><USER197> How long would it take to get from San Fran to LA?

Edit: nevermind, it is about 30 minutes

</comment><comment><USER110> Although Musk has said this idea stems from his frustrations in traveling through California, I wonder if he's contemplating something similar for transportation on Mars?

<comment><USER198> Well, you would no longer need to evacuate the tube...

</comment></comment><comment><USER199> Let the tech workers test it out on their SF-Silicon Valley commutes first. Maybe Elon's musk will help convince all the millionaire tech NIMBYs that own the peninsula.

</comment><comment><USER200> I was thinking that a well-timed explosive charge on a support pylon would make for a nice mess, but I suppose it's not any easier to secure a conventional railway.

<comment><USER165> The distance between the pylons is small enough that adjacent pylons may be redundant. It's also a _massive steel tube_ which would be pretty strong in itself compared to rails (or roads).

<comment><USER201> The tube itself also isn't bearing nearly the same load as a train track.

</comment></comment></comment><comment><USER202> I think it's interesting to devote so much space in the introduction to hypothetical supersonic air travel. Might this be what Musk actually intends to do next?

<comment><USER203> In an interview last we he stated that his next company would be vertical take off supersonic electric jet, if he decided to start another company. He said he's not likely to start another company any time soon.

</comment></comment><comment><USER204> What is the feasibility to construct one within a metropolitan area, like Greater Boston, Bay area etc. Example: One between South bay and SF in the Bay area?

</comment><comment><USER205> My dad has worked on at least one proposal for linear rail in California in the past. Emailed him the whitepaper for comments. Delivery not guaranteed :)

</comment><comment><USER206> Just remember people, the real future of travel is SpaceX, not Hyperloop.

The final frontier is space, not San Fransisco.

(I am wide eyed and crazy about the Hyperloop)

<comment><USER207> the real future of space is Hyperloop v2.0 - 20 miles long or something like it, pointed at the end toward the sky with final exit speed of let's say 10 Mach (and this also will help to reach Hong Kong from SF in 1-2 hours)

</comment></comment><comment><USER208> So who's starting the Kickstarter campaign?

</comment><comment><USER209> Ah – a turboprop tubular-ground-effect vehicle.

</comment><comment><USER7> Something interesting my friend said: this would make an awfully good roller coaster.

Could that be a path to getting it prototyped, profitably?

</comment><comment><USER208> To put the the 7 billion cost in perspective...that's approximately the cost to build the new segment of the Bay Bridge.

</comment><comment><USER138> If Musk really wants to give this a push, how about a patent grant on Tesla battery patents used for this purpose?

</comment><comment><USER210> A thought I just had, could a hyperloop like technology be used to launch ships into orbit? Why or why not?

<comment><USER6> Not by itself, but maybe in combination with another technology: [http://www.popsci.com/technology/article/2010-11/nasa- engine...](http://www.popsci.com/technology/article/2010-11/nasa-engineers- propose-combining-rail-gun-and-scramjet-fire-spacecraft-orbit)

Whatever you were launching would have to move through normal air, not the minimal pressure you have in the Hyperloop tube. It is hard to pass an airlock at supersonic velocities...

<comment><USER210> Could you gradually re-introduce air pressure at the end of the tube before the payload exits towards orbit?

</comment></comment></comment><comment><USER211> One of the few times I've read the word 'pylon' without being concerned with some video game.

</comment><comment><USER212> After reading about the benefits of putting the track on pylons I was strongly reminded of monorails.

</comment><comment><USER213> It might not be built in real life, but somebody should at least build it in a mod for GTA5.

</comment><comment><USER149> Why not build a tube around the span of earth? A joint world project.

</comment><comment><USER214> My travel nirvana: Supersonic air + Hyperloop + Self Driving Car.

</comment><comment><USER215> This is such a cool concept. I was so hoping he would build this.

</comment><comment><USER216> I have never been more excited for a coming soon page.

</comment><comment><USER217> i would say that it is marketing if the guy did not own SpaceX. Still I am skeptical. Every child can draw neat pictures and speak about vacuum.

<comment><USER103> I would read the pdf before commenting, this is a little more than some pictures.

<comment><USER218> Yes, it's a whole PDF!

</comment></comment></comment><comment><USER219> A "coming soon" page is at the top of HN?

<comment><USER220> It should have been already published (at 1:30 pacific time.) [https://twitter.com/elonmusk/status/366964441159438337](https://twitter.com/elonmusk/status/366964441159438337)

<comment><USER221> SpaceX has a history of failed launches before settling into a routine of spectacular success.

Hopefully their inability to publish this page on time will prove to be another example of the same. ;-)

</comment></comment></comment><comment><USER222> It's there now. No longer a holding page

</comment><comment><USER223> Is that a jet turbine in the nostril?

</comment><comment><USER224> first thing that popped in my mind when I heard about the hyperloop was hank rearden

</comment><comment><USER101> Jerry Brown: Build this tube!

</comment><comment><USER225> HYPE*rloop

</comment><comment><USER226> its up now

</comment><comment><USER227> Does the government give it a fuck?

</comment><comment><USER228> Appreciate Elon Musk for this idea. But do you really want a bus sized hunk of w(ever)tf this is made out of zipping by you at 700mph?

<comment><USER59> Bus-sized chunks of metal are flying over your head every day. They're called "airliners".

<comment><USER228> That's true.</comment></comment></comment>