As a longtime gamer, this article really struck a chord with me. Dragon magazine used to print playable adventures, and in August 1981 (I just went and looked it up), there was a Gamma World adventure called "Cavern of the Sub-Train."
The player characters in their post-apocalyptic world come across a abandoned series of tunnels they can't explain, but which are described for the game master in the notes:
The system once spanned the North American continent and was used primarily as a method of high-speed transportation of freight. The sub-train system is something like a 20th-century subway system, in that it consists of a self-propelled train moving through an underground tunnel. Unlike the 20th- century system, however, the “trains” moved through a vacuum while being supported on super-conducting magnetic rails at very high speeds.
Thanks for your post. Having big dreams of the future is crucial to making that future happen.
Many posts below are trying to prove how smart they by focusing on near term impracticalities. Sure it's impractical today. That's already proven by the fact that it is not already under construction.
The surest way to be wrong is to say something can never be done. I'm not even advocating this is a good solution. I have no idea if it will ever be possible. But I enjoy seeing that some people are thinking big.
Good luck holding a vacuum under the ocean. I read stuff like this and I think, "Gee, I don't think these people have actually built anything." because if they had they would realize that if it costs $1M a foot too build subways  in cities with moderately skilled labor, its going to cost $10 - 25M/ft to build something like this. That's half a quadrillion dollars (448 trillion dollars). What sort or rate of return do you think you would need to make that feasible?
I'd love someone to actually do a credible cost analysis of an evacuated tunnel train. Unfortunately I don't think Oster did.
It's probably more reasonable to compare the costs of this tunnel to undersea tunnels like the Seikan Tunnel (33 miles, $3.6 billion to build in 1988) and the Chunnel (31 miles, $21 billion in 1994).
1988 $3.6 billion = ~$7 billion today.
1994 $21 billion = ~ $32 billion today.
Put it altogether, the tunnel itself would be around $3.5 trillion. Maglev + vacuum stuff would cost more.
Just think - we could do three or four megaprojects a year with a 2006-esque budget elsewhere plus those kinds of budget deficits.
Of course, as anyone in California is painfully aware, the high-speed rail project is a complete joke :) you'd need to trust that this one would do better.
Also, as an economics aside: In the private sector, a $280 billion project should hope to earn in the neighborhood of $11 billion a year in profit/savings in order to cover the cost of capital. This is, of course, after equipment maintenance, fuel/power, deprecation, labor, etc.
That's what I've been thinking as well. This might be an unintended consequence if SpaceX is able to reliably deploy the reusable rockets they are drawing today. It might actually require less energy to launch a passenger vehicle above the atmosphere and let it glide/freefall all the way to the destination than it does to push the same vehicle through the atmosphere. I haven't actually done any calculations, though. It would be interesting to see how much energy it would require per passenger to get such a vehicle to a suitable altitude and speed for intercontinental flight. For instance an aircraft powered with combustion engines, with booster rockets attached.
The disadvantage of your solution is the environment impact of such a transportation system. An electricity based solution seems to be much cleaner (especially if we imagine the same kind of traffic as the plane one today).
For varying hardnesses of vacuum, you can find a partial vaccum of 4 psi at 30,000 feet.
Which is enough to drop drag a lot, and still maintain lift in, say, commercially viable air transportation vehicles.
Lowest costs I've seen to LEO are about $1,000/lb. Suborbital flight isn't much lower than that, and we're still looking at something on the order of $10k - $1m per passenger at rates like that. Affordable to some, but (considering you've likely got a baggage, life support, and related allowance) pretty pricey all the same.
$10k is comparable to Concorde, as I recall. I consider that a very optimistic estimate.
A vacuum only weighs 1.28 grams less per litre than air. Since there are 1000 litres in a cubic meter, a 3x3x3 meter cube (approximation of a cross section of a unit of the tube) would contain 27000 litres whose air would weigh 76 lbs.
In other words you're talking about sinking 3 meters of tube that would weigh 76 fewer pounds than if there were air. This is probably a small effect compared to the weight of the strong metal casing that would need to surround such a vacuum.
So since we can sink normal air-filled subways quite normally (e.g. the BART in San Francisco) this must be a well-established technology.
Well I was responding to a specific poster who focused on a different issue. Steel tubes can easily withstand a vacuum... a round tube is an extremely strong structure. Sure the joints between pieces would be the harder part, especially with earthquakes and the like forcing flexibility.
Other countries with different building laws have very different costs. Say what you will about Spain, they can build subways or rail for one tenth as much as it costs in the US. French and British trains are also, I believe, much cheaper though not quite that much.
Daryl Oster's company has submitted proposals to Florida, at least, on building and maintaining a system such as this. I think part of the requirement for submitting such a proposal is at least a cursory cost analysis. Wikipedia reads a bit like the company wrote it itself, but:
The firm fixed bid for the 96-mile (154 km) Evacuated Tube Transport (ETT) system was $253M, this was less than one tenth of the cost of the bid by Global Rail Consortium to build electrified double track High Speed Rail for $2.6B. The bid by et3 contained letters of support by three entities in China to supply IP and key materials for the project. The engineering consultants hired by the authority did not dispute the validity of the et3 bid price or ETT technology, but recommended to eliminate the et3 bid from consideration for other reasons.
This comment doesn't pass judgment on whether Daryl Oster is a patent troll or not, but that's also a discussion worth having.
Would love to see how they costed that out. Given that I don't know of a single engineering company that can build straight up light rail track for at $2.5M/mile even if you give them the land for free.
Edit: add this update --
Interestingly this link: http://www.freerepublic.com/focus/f-news/843626/posts claims that the ET3 bid was 1.2B$ which is $12.5M/mile which is a lot more credible (still low though since the surrounding infrastructure to keep the tube evacuated, the mag lev stuff, etc all add cost over regular fused rail electrified service (which California is considering for its fast rail) and that is looking closer to $25M/mile in the current state of the art)
That is a great question, I wish I could reasonably answer it. I'm a big fan of rail, and while San Jose was celebrating their first 4 miles of light rail (in just 10 years from the start of the project!) I was looking that the marker in the Sacramento Rail museum (recommended) commemorating the laying of 10 miles of the Union Pacific rail line in one day.
Part of it is that some folks really hate rail, so much so that they will continually sue anyone who is working to build it. They will argue wildlife endangerment, habitat destruction, cancer risk, suicide risk, traffic risk, earthquake/disaster risk, global epidemic risk, job preservation/creation/destruction risk, you name it. Anything to get back in court and have a judge temporarily suspend work. Because you hire someone to work on a project, and they can't because of some court order, you still have to pay them. So what happens is these projects have 'burn rates' (which is the cost of renting equipment (or depreciating it if you own it) and labor and materials (some of which degrade over time if not used)) and then you have 'able to work' days. Actual work days might be 90 for a mile of track, but time actually passed is like a year. So the other 275 days people sat on their hands while expensive lawyers argued to get work restarted.
Its one of the things I bring up at town hall meetings with politicians. The tax payer, and the 'NIMBY'  folks, fight a very asymmetric kind of warfare. No court challenges until funds are committed, and then six. You need look no further than the maneuvering around the California High Speed Rail project to see it play out in all of its ugliness.
 NIMBY -acronym Not In My Back Yard for people who are opposed to any new infrastructure near where they live.
Haven't you just proven that your initial post above is irrelevant to an undersea rail system?
I'm not saying an undersea rail system is practical or smart. I'm just asking the relevance of your comparisons to US urban construction costs to begin with.
As a suggestion, a different tone might make your post seem more useful and less trollish. For example "An undersea tunnel will require serious construction breakthroughs to be practical. As a comparison, today's costs...". That would be a lot more constructive than attacking the people behind the article.
Great feedback, thanks. The conversation wandered a bit, and while I don't think of my style as trollish I can certainly see how my emotion on rail interferes with my communication.
My initial point is a prima facie argument, the proposal is impractical by inspection. I certainly stand by that assertion, but as part of the supporting argument we've been discussing land based construction with the implicit, albeit not as well supported, stipulation that sea based construction would always be more expensive than land based.
An interesting way to approach the problem would be to outline the design space in terms of operation cost, development cost, and rate of return and see what sort of solutions, if any, might fit inside that box.
>San Jose was celebrating their first 4 miles of light rail (in just 10 years from the start of the project!)
> Actual work days might be 90 for a mile of track, but time actually passed is like a year
So currently, San Jose can build 0.25 mi/year. Optimistically, with no lawsuits, their actual work days could increase to say, 225 days/year, which is 2.5x faster. So we're up to say, 0.66 mi/year, which still sounds way too low. What are the other bottlenecks?
Well one of my political suggestions to 'even' the playing field was to create a certification date for a project after which no lawsuits could be brought against it. This would give the project planners a way to budget the years of litigation, and once they were certified they could start and continue until they were finished without interruption (except for the usuals, weather, labor disputes, and material shortages).
I've gotten some positive feedback for that but have yet to find someone willing to actually submit it in a bill.
Isn't this part of why rail is a lot easier to do in Europe? My understanding is that it is a lot harder to sue over stuff like this there. Maybe someone familiar with Europe's rail situation can chime in.
The process is definitely different at least in the smaller countries. In Denmark, when the Copenhagen metro expansion was agreed on by the government, the plans were passed as a law through the national parliament. Therefore, everything in it became by definition legal, superseding any contrary legislation, unless it violated the constitution.
The U.S. instead tends to work on a model where the legislature passes general rules, and then agencies administer the rules in specific cases. So, for example, a specific rail plan is proposed pursuant to a piece of legislation, but the plan is not itself a piece of legislation superseding others. That leaves it open to all sorts of lawsuits alleging that it didn't comply with the legislation that applies to it.
I feel that most of the cost is for tunneling and the difficulties of working in such a space as a subway system. as for normal railroads, a quick googling shows that the cost is much more conservative, with a 1995 estimate stating about $250,000 per mile to rehabilitate an existing railroad.
A large chunk of the costs of projects like this is building the long flat tunnel/level ground over significant distances. The actual costs of building a moderate vacuum is not that significant. Where this project falls down is in the maintenance and safety side of things not the infrastructure to send the first train down the line.
Don't forget every 10m adds 1atm water pressure. Building a glass enclosed under sea walkway 30m down is not that much harder than building one 20m down and these projects are going to be using glass.
> a glass enclosed under sea walkway 30m down is not that much harder than building one 20m down
It's 50% harder.
What pressure are the passengers exposed to?
I ask because 1 hour @ 4 atmospheres of 80% N2/20% O2 is risking decompression illness. (Yes, 4 - you've got 1 atmosphere at sea level.) You can reduce that risk by increasing the O2 percentage but if you do that too much, you're risking O2 toxicity.
Firstly: As I see it, an evacuated tunnel at 20m is a very different proposition to a non-evacuated tunnel at 30m, even if the pressure difference is the same. Why? Well, your big problem is always going to be leaks. In an air-filled tunnel you can get away with microscopic cracks, no problem; you've got a small direct interface between water and air, and the surface tension of the water is enough to keep the water in place. It's very hard to force water through a really tiny crack. In a vacuum, however, surface tension goes away -- liquid water at an interface with vacuum will boil, and all of a sudden you've got water vapour filling your nice evacuated tube through every microscopic crack in its five thousand mile length. Nasty. Clearly the joined-concrete construction used for the Transbay Tube isn't going to be sufficient.
Secondly: unfortunately the Atlantic Ocean isn't 20m deep, or 30m deep, or even 40m deep like the deepest point of the Transbay Tube. It's several kilometers deep.
Is there some reason that sandwiching air between the evacuated tube and the water wouldn't work? Granted it would add to the cost.
The ocean depth point is interesting. The article says "engineers would tether the tunnel at a fixed depth." I take this to mean tethering to the bottom and relying on buoyancy to keep the tunnel floating at the right depth, which presumably could be 30m or so.
>Is there some reason that sandwiching air between the evacuated tube and the water wouldn't work?
Yep, because now you've just got your air rushing into the vacuum through the cracks, instead of water.
The ocean depth point is interesting. The article says "engineers would tether the tunnel at a fixed depth." I take this to mean tethering to the bottom and relying on buoyancy to keep the tunnel floating at the right depth, which presumably could be 30m or so.
Even if you could get it to be neutrally bouyant at 30m (realistic estimate? dunno) you're now stuck with a tube, five thousand miles long, floating free in the ocean and anchored only to the bottom. Even neutrally bouyant, there'd have to be huge strains on the joints due to ocean currents, plus presumably some up-and-down forces as the season changes the water temperature and... heck, even a whale headbutting such a flimsy structure sounds like a disaster waiting to happen. And remember, you can't afford to get any imperfections in your tube or it'll leak -- that probably eliminates anything you might have used to build in a bit of flexibility.
>Yep, because now you've just got your air rushing into the vacuum through the cracks, instead of water.
Fair enough. I imagine there's a trade-off between the quality of the tunnel materials and the number of pumps needed along the way, assuming an imperfect vacuum is good enough.
I'd be worried about flexibility too. Skyscrapers do pretty well in high winds and earthquakes, so I'm not completely convinced that a similar effect isn't possible with an underwater tube. Any bending would have to be extremely gradual, though, if there's any hope of shooting something through it at high speeds. I agree that glass isn't going to cut it.
Another megaproject supporting my theory there's a market for promoting - not building, just promoting - projects so large, expensive and outlandish that a small team can make a decent buck thereon. A miniscule percentage of half a quadrillion dollars nets a few million for research, marketing & salaries.
This idea's been proposed on and off for some decades, and is definitely intriguing. The crucial problem, though, doesn't seem to be the technology per se (though there are undoubtedly large risks there, too), but the back-of-an-envelope economics being anywhere near sensible enough for someone to dedicate serious money to it. Before anyone is going to build a London-to-NYC line, my guess is that you'd have to first show some kind of much smaller-scale demonstration, like how there were test maglev lines built.
In a quick Google Scholar search, I turn up a 1974 article on "Surface-guided transport systems of the future" (http://dx.doi.org/10.1049/piee.1974.0277, unfortunately not open access), where evacuated-tube transport gets a mention, but under this less-than-enthusiastic banner:
A brief mention is given of other less likely transport systems, such as travel in an evacuated tube beneath or above the ground.
If al Qaeda blows up a pressurised train tunnel, then yes they can kill lots of people, heap a big cash cost on the tunnel operator... but they don't get any impressive pictures to put on TV.
If the IRA/ETA/etc blows up a pressurised train tunnel, they impose a big cash cost on their target, plus cause lots of disruption... but in terms of effort/risk/reward it's probably better for them to blow up conventional rail/road infrastructure in London/Madrid/wherever.
Scale of attack, amount of force required, social and economic impact of the accident.
Look over a list of who the victims of the Titanic disaster were -- comparable in that it was the luxury travel alternative of its day. Jay Jacob Astor, Benjamin Guggenheim, Ida Straus (founder of Macy's), just to name a very few. The societal impact of the Titanic's loss was ... titanic.
You wouldn't even need an explosive to foil the tube. Simply something to perturb the system slightly would disrupt it in a bad way. Even if only a single small transport were in the vicinity, any others in the tube would also be doomed (granted, at 1 hour/trip, headways would likely limit this to a very few instances).
Strikes me more that the potential for damage is higher here. A pretty small explosive charge would compromise part of the tube, and then what happens to the pods zipping along at 2,500mph inside them when the air comes rushing in? For that matter, if they did have an underwater tube connecting London and NYC, the water would come rushing in and you know that's not going to end well.
It sounds pretty cool - it's the kind of sci-fi thing I'd love to see in the real world, but I can't believe it's as easy or as cheap as they're making it sound here.
They aren't going to dig a tunnel through rock all the way underneath the Atlantic - that's many times further than the Chunnel, and that was a serious undertaking. The article implied it'd be underwater.
The tunnel itself will be formed of solid material, they don't need to go underneath the sea bed they will put their own construction in. That is what the tunnel will be, it's not just a vacuum in the middle of the water.
Obviously the tube would have to be incredibly strong, since it will have to withstand the water pressure at whatever depth it's at. I'd be curious to see calculations on that, as well as repair costs. Also costs for land-based vs sea-based.
Well, airplanes are a considerable distance up in the sky and incredibly difficult to reach. It's why the vast majority of plane-related "badness" happens shortly after takeoff or shortly before landing. Any land-based rail vacuum tunnel would not be protected in this way. An underwater one would be to an extent- I suppose it depends how deep it goes. But it's still a lot easier to drop something (say, a bomb) into water and let it sink than it is to fire it into the air and hit a plane.
5 times the speed = 25 times the kinetic energy (per kg). And that is for the 'slow' one. At 4000mph, it is more like 64 times. And yes, this only talks of a 6-person capsule, but I think you would need to send quite a few of them through that tube to make it economically feasible. You wouldn't need to bring explosives to destroy the tunnel. Just have enough to have a 10 kg or so part drop from one of those capsules.
I never have understood people's fears about getting on an airplane... this though I'd be scared to death of. You have any unfortunate shift in the tectonic plates (which happens daily and unpredictably) and you could be dead in an instant.
I gather that the intent is to tether the tunnel. I've seen how cables are run in tectonic-active areas: they are provided a certain elasticity and I imagine it would be similar. Earthquakes don't move much more than a few meters at a time (for a very very large event). How would this be any different than the Chunnel?
My own comment on this article:
"getting to, from and through airports is very time consuming"
I don't see how this would be any less time consuming. Security would be an equal nightmare - the only benefit would be that the citizens can utilize NYC/Londons existing transport infrastructure much like it's easier to get to the Chunnel departure station than it is to get to Gatwick.
Oh, yes, security! Strange this isn't discussed more. While a bomb in an airplane is bad enough imagine what a ripped vacuum tube under the ocean will do! Such a tube will be a high profile target for terrorism and an incident/accident would block/destroy the whole traffic.
Here's how the Japanese high speed trains deal with earthquakes: They have emergency break systems (I think its small ceramic globuli or something of the sort) and a really good forewarning system. 2011-3-11 all Shinkansen were at a halt when the big one hit and noone was harmes on them. I don't see why you couldn't do the same here.
Because if the rail line cracks (which probably did appen in Japan), water floods into your tube. Then it becomes a question of "can they rescue you before your air supply ends" (since they would require an air supply for the vacuum)?
Oh, this post was in reply to the underwater part? Yes, I also think that this one isn't feasible for quite some time. My reply was in response to vacuum tubes over sea level. Right now we can't even have floating tubes anchored to the sea ground yet; storm waves rip every anchor we can build apart (it has been tried for wave power generators).
Vacuum tubes could probably be built deeper down where the waves aren't strong. I actually think that earthquakes wouldn't necessarily be a problem at that level, since everything would have to be quite flexible anyway. In order to elevate security, I could imagine making tube sectors detachable and having safety shutters. This way, if one sector is breached it could be sealed and detached such that it floats to sea level. The train could even be inside if you can control the pressure differences well enough to not kill everyone inside (something that is well understood for jet planes).
Since it's an interesting mindgame I thought about it a little further: There IS a hard problem to solve here: If your train takes 5min to stop from 4000km/h, its breaking distance would be 166km (assuming linear deceleration)! This means that you could only shut down sectors further away than 166km from the closest train - all sectors within are your vulnerable zone. That seams quite risky to me. On the other hand we do fly millions of people a year in pressure cabins with no way to escape. Since with this new system people's life would depend on tubes 160km long instead of 70m (length of a 747), all you need is materials that are 2000 times more reliable than those of our jet planes. While being emerged in seawater. And enduring a much higher pressure difference. Yeah.
I'd say let's wait and see what nanotechnology gives us :).
Good point. Obviously you would have to restrict the applied g-forces, therefore the time to stop would be longer. If I'm not mistaken, this should only a linear relationship though, e.g. if you restrict the acceleration, the time to do 10x delta_v is 10x the time you need for delta_v. As long as the earthquake forecast is good enough, this should be manageable, e.g. you need 300 seconds instead of, say, 30. 5 minutes forecast seems realistic to me. Obviously you can never give 100% safety - if the epicentre of a big quake is right underneath your trainline you might be screwed; However that chance is really small and we already live with these kinds of risks today.
I think the main issue is being trapped in an airless tunnel several hundred feet under the middle of the atlantic ocean. That is a far cry from 'train stopped on tracks in the middle of a field'. Frankly a stopped train sounds like a great place to ride out an earthquake - far better than many buildings.
Much cheaper to go the suborbital flight route. Anywhere on earth to anywhere on earth in 2 hours.
Less infrastructure required. (And today anything requiring massive governmental infrastructure commitments is doomed to fail)
Cheaper? You have much greater energy losses from atmospheric drag, firing hot gas out of your back end is far less efficient method of acceleration than electromagnetic propulsion, and you can use regenerative braking.
In theory setting this up should be much cheaper than high volumes of suborbital flights.
I live in NJ, about 4 miles away from my office in Manhattan and I have a 45 commute. Can anyone figure out how to solve that problem? It's a lot of fun to kill the afternoon talking about something that's never gonna happen. In the meantime, millions of people are wasting days a year crawling to and from work.
Get a pushbike. Persuade everyone you know to get a pushbike. Make them persuade everyone they know to get a pushbike.
Start a campaign for people to only use their cars if they i) Have to or ii) are travelling over 10 miles.
Make workplaces have facilities for cyclists. (Perhaps going as far as treating car-parking spaces as a taxable perk). Make schools have facilities for cyclists. Make shops have facilities for cyclists.
Persuade the bad cyclists to stop being idiots. etc.
There is a river in between. You would need to bike up to the George Washington assuming he lives in Hoboken and commute to Midtown. Either way you go from a 45 minute commute to maybe a 2-3 hour commute if you are lucky. Even worse since now using a bike his commute is ~20 miles instead of the 4 in the first place.
You are responding to me, the person whose problem you think you solved. I take a bus that costs $98/month. The ferry is over $300 for a monthly pass. If I want to take the ferry tomorrow, with my bike, for example, it'll be about $20 for a daily round trip. My best option would be to taking a folding bike so I can take a train. That would work on nice days.
However, what I'm really asking for is to solve the problem for the millions of commuters. It's crazy that people waste so much time commuting.
a. move your home closer to work
b. move work closer to your home
c. move both
you're traveling 4 miles, across a river, into one of the most densely populated cities in the world. there's bound to be some friction. that said, you could probably live 4 miles away in brooklyn or queens and be at work in 15-20 minutes.
The Concorde made day-trips US/Europe possible, but had to face the fact that there simply is no satisfying market for such high prices. And submarine vacuum trains would be much more expensive than a plane on steroids.
I've met Daryl Oster, the guy behind ET3, even contributed a few ideas crudely sketched out on a notebook -- stuff I'm sure somebody involved had already considered. Anyway, he seemed nice, smart, legit. I really love the basic idea and goals of ET3. I was a little bit concerned that it wasn't farther along in terms of implementation versus theory. But he did say that he's worked with folks in China and they were generally much more receptive to it there, whereas in the US there's more bureaucracy and legacy inertia. There's right-of-way issues, NIMBY, legal stuff. I think all the edge case scenarios are riskiest -- those need to be addressed in the design, if they can be, things like what happens if a tube is pierced, what happens if a passenger has a crisis and needs to get out of it quickly, etc. But the basic physics of it are pretty attractive because of the efficiencies and economies of scale.
Yep, globe-spanning underground maglev/vactrains, which in the future-history of Genesis II (1973) and Planet Earth (1974) had been built in the late 20th-century and survived world war to be still working over a hundred years later.
The sci-fi of the past was way too optimistic about giant-scale engineering projects at the same time it was blind to advances and trends in communications and computer-mediated collaboration.
I'm absolutely fascinated by the difference in responses I see on HN versus talking to my friends (liberal arts). They were concerned with the future implications for cultural integrity as well as how it would effect labor forces and capitalism as a whole. Any thoughts?
I, for one, think this technology is awesome and think it could follow the progression that the train system went through in the US (transcontinental railroad, expanding, webbing out, lightrail, subways, trams, metros, etc) and see this as a possible next step in the evolution of transportation.
It seems the media blitz in the west has had the intended effect when so many people respond to such an idea with "but turrerists!". Driving cars on the highway is a much higher risk to your safety than terrorists ever were or ever will be. Don't give up on the future because of paranoia and irrational fear.
Doesn't a gravity train actually seem more appropriate here? It doesn't need to go through the center of the earth in this case, and is shorter distance than a tunnel. The only problem is it probably takes a lot longer to build.
Velocity is imperceptible, since it depends on a frame of reference. For example, I'm traveling at about 700mph around the center of the Earth because of the Earth's rotation.
Acceleration is perceptible, because it is felt as a force. So it really depends on how quickly people are accelerated to 2500mph. If you accelerate at 22mph per second, this is equivalent to 1G, which could be relatively comfortable. It would take 2 minutes to reach 2500mph.