Why Ultra-Efficient 4,000 mph Vacuum-Tube Trains Aren't Being Built 625
cylonlover writes "In the 1800s, when pneumatic tubes shot telegrams and small items all around buildings and sometimes small cities, the future of mass transit seemed clear: we'd be firing people around through these sealed tubes at high speeds. And it turns out we've got the technology to do that today – mag-lev rail lines remove all rolling friction from the energy equation for a train, and accelerating them through a vacuum tunnel can eliminate wind resistance to the point where it's theoretically possible to reach blistering speeds over 4,000 mph (6,437 km/h) using a fraction of the energy an airliner uses – and recapturing a lot of that energy upon deceleration. Ultra-fast, high efficiency ground transport is technologically within reach – so why isn't anybody building it? This article looks into some of the problems."
Maybe because... (Score:5, Informative)
When the British did it [wikipedia.org] they had hella mechanical problems. The smallest glitch with a seal and suddenly your trains aren't moving nearly as fast anymore. You'd have to build two tunnels: the vacuum tunnel for the train, and then a slightly larger outer tunnel that allows for service and leak detection.
Not buying my tickets yet .. (Score:5, Informative)
Wake me up when someone actually manages to build a tunnel anywhere near that size that's vacuum tight and has a realistic notion of what size and number of vacuum pumps would be required to keep a high enough vacuum in it. Oh, and handling the exterior pressure loading without risk of accidental implosion would be nice. ;)
The other problem which is less trivial than it might seem is how to get people and cargo (and possibly vehicles) onto and off of these trains without breaking the vacuum .. really big airlocks at the stations maybe? .. and how to evacuate one of these safely in case of an emergency on the main line ..
Re:in the year 3000 (Score:4, Informative)
hopefully the passenger dispersal method will be safer than just dumping us on the curb
Fire - Catastrophic Fire Risk ... (Score:4, Informative)
The reason the vacuum systems went out of favor was the massive associated fire risk. At first, it doesn't seem obvious why a vacuum system would have a fire risk, as in theory the vacuum should extinguish the fire. However, this doesn't work in practice.
What actually happens is the fire starts outside the vacuum system, where it has access to air. The fire then causes this air to expand. The logical place to expand is straight into the nearest low or negative pressure environment around, which is the vacuum system. In no time at all, the vacuum transportation system spreads the fire between floors - and disaster ensues.
Vacuum transportation systems used to be popular in multilevel buildings of large companies. Then one by one they caught fire. Eventually, the fire codes understood the significance of plenums and air return systems in spreading fires. Now any kind of vacuum, plenum, or return air space that stretches between floors has special safety devices inside it. They are extremely dangerous spaces if fires occur.
Additionally, vacuum systems were never used to transport people, because if air integrity on the capsule fails, then everyone suffocates.
Re:kinetic energy (Score:2, Informative)
The article has it right. When dealing with changes in energy you have to consider the frame of reference. From the train's frame of reference, which is moving with respect to the Earth's, any incremental change in velocity results in the same change in kinetic energy. Consider this thought experiment. You are on a stationary train. You stand up and begin walking forward at 5 mph. Later the train is moving at 100 mph. You stand up and walk forward at 5 mph. From your point of view the change in kinetic energy both times was the same. It did not take more energy for you to walk on the moving train vs. the stationary one.
Re:Perhaps.. (Score:4, Informative)
I can't imagine any sort of high speed mag lev line will have any sort of real earth quake tolerance, but maybe I'm wrong
Yes, you're wrong, and if you'd thought for a few seconds, you would have realized it. Japan does just fine with their bullet trains, despite having plenty of earthquakes.
Come on AC, don't be a jerk, explain why. The reason why earthquakes don't matter in civilized country with trains is data travels around the speed of light (well, Vp correction factor, but pretty GD fast) and earthquake waves travel at the speed of sound in rocks (well actually compression waves go a different speed that transverse waves but whatever). The point is the ratio is ridiculous. So you have earthquake sensors everywhere including deep in mines and wells and even in worst case scenarios you can get warning minutes before the quake hits the train (no kidding). Now 4000 MPH is faster than sonic so if you're headed away you ignore it, the wave isn't going to hit until long after you arrive at destination. If headed toward, well you got issues, but 4000-0 is not really all that long. A spacecraft like the shuttle never peaked above 3 G but went 0 to 18000 in what 9 minutes or something? So if you're willing to risk 10G I think you can stop pretty darn quick.
Its the same reasoning why satellites save lives in hurricane areas... yes the satellite is much further away than the hurricane, but even so, the radio waves get to the shore long before the hurricane arrives...
Re:Space Elevator (Score:5, Informative)
Vertical travel is a very different proposition. Compare the energy usage for a person standing at the top of the Empire State Building and a person standing in a helicopter hovering a few metres away. Both are at the same height, but one is having to use fuel (in quite significant amounts) just to stay in the same place. Now have the man in the building go up and down the stairs for an hour and have the helicopter maintain the same height as him. At the end, compare their energy usage.
In contrast, for something like a train the majority of the energy is used in acceleration. Reducing air resistance and rolling resistance give some benefits, but it's not huge. The advantage of the hypothetical maglev vacuum train is that it can keep accelerating for as long as it wants (air resistance increases with speed). This isn't really useful for most trains, although it would be useful for something like a transatlantic or transpacific railway where you'd have a long distance and nowhere where you might want to stop on the way.
For reaching orbit, a space elevator means you don't need to carry as much fuel. Over 90% of the mass of a rocket going into orbit is the fuel required to carry the fuel into orbit. Take that away, and you've made a huge saving. If you can power the climber from the ground, it's even better. Acceleration is also an issue. A rocket must accelerate at more than 1g just to move upwards. Because of this, it must accelerate hard so that it doesn't run out of fuel just maintaining the 1g needed to stay in the same place. A climber can maintain a constant speed or a slow acceleration.
The main reason we haven't built a space elevator is that we've only recently made materials in the lab that are (probably) strong enough to be used for the tether, if we could work out how to mass produce them.
Re:Simple (Score:5, Informative)
Trains only work when government subsidizes them. FOR the cost of the new California High Speed Rail, that won't actually be useful until just before it is completed (i.e. nobody could ride it anywhere useful), you could give every man, woman and child a whole bunch of passes on Airlines from more places in the state than the CA HSR would actually go. And it would take less time to travel to said places. And cheaper.
The way I explain it, we already have HSR, they are called Airplanes. HSR was designed for one thing only, to curry favor with the Unions that will build and run them. It is a Union Make Work Program .
Here's the math ...
Cost of the HSR system (current est) 65,400,000,000 (this is nearly 50% more than the ballot said it would be) It will be much higher when all is said and done.
Actual Population of California 38,000,000
Short versions of the numbers 65,400 / 38 = $1721 per man/woman/child
Cost of a plane ticket $68-$250 one way. That is SEVEN free (high cost) tickets per man woman and child in CA. THIS does not count the actual cost of the ticket to ride the train. And all the projections, even from the Rail Authority, tell us that the cost will have to be continually underwritten by the tax payers.
I have yet to have a person make any sort of reasonable argument why we should spend that kind of money in a state that is going broke.
Re:Simple (Score:5, Informative)
You guys always point to reality...as a defense for your delirious mental illness about space. Doesn't work that way.
Ummm...yeah. What do you want people to point to instead? The Starship Enterprise? That's kind of the the point. You say that ${futuristicConcept} can't be done because of insurmountable technical obstacles. Other people point to ${formerFuturisticConceptThatIsNowReality} as a counter-example of something once thought impossible, but now taken for granted. For years, people said it was impossible to fly in a heavier-than-air, powered aircraft...then our friends Wilbur and Orville (or Glen Curtiss, depending upon who's revisionist history you choose to subscribe) did it. People thought that rockets couldn't "fly" in a vacuum because there was "nothing to push against." Then the Russians launched Sputnik. All (or at least "many") experts said we will never exceed the speed of sound...then Gen. Yeager did it. The point of all of these examples is that people thought a number of various things were impossible...until someone figured out a way to get around the obstacles that people thought were "insurmountable." Griping that pointing "to reality" to argue that things are only impossible until someone accomplishes those things is, in fact, the way it works.
Those things were built because they were able to build them...
True statement is true, yes. Your point?
What you are blatantly ignoring is that people didn't think those things were possible -- exactly as you don't think various things are possible now. The problem wasn't that things were intrinsically impossible; it's that people were approaching the problem from pre-conceived notions based upon the limitations of existing technology. In what way are the things you currently say are impossible merely limited by our current understanding of physics? This may come as a shock to you, but...(wait for it)...we don't know EVERYTHING yet. Therefore, we can't predict what "impossible" things will become possible when some "Eureka!!!" moment shows that something we all thought we understood gets shattered wide open by a new discovery. When we get that insight, things that we thought were impossible might suddenly become trivial.
Re:kinetic energy (Score:5, Informative)
Re:Simple (Score:5, Informative)
If you planned ahead, and had the relevant travel card, that price goes down to EUR79 (USD100).
That journey is a little over 6.5 hours on the train. You'd be lucky to do it under 6 hours driving, factoring in relevant breaks and depending on where in each city your arrival and departure point was. If I had anything to do at the other end, I know I'd much rather travel by train than bust my butt driving.
I regularly catch a tran from Vienna to Graz in Austria. The cost is around EUR18 one way, with discount card. The journey takes 2.5 hours by train, and maybe 2 hours by car, depending on the traffic. On the train I can read, work on my laptop, sleep, walk around, go to the dining car etc. It's a much more pleasant way to travel.
Re:The only answer for the USA (Score:4, Informative)
Re:Perhaps.. (Score:4, Informative)
Thanks for that. I actually snorted out loud. Trained marines in pressure suits with the force vector compacting the spine are reduced to peering through a constricting black tunnel in their field of vision in the desperate attempt to not black out before the missile passes.
I've heard -3g (e.g. non-inverted power dive) described as having an 800lb gorilla sitting on your shoulders squeezing your head between his thighs as if he's nearing his moment. Pilots rarely try this twice.
If people are facing forward wearing lap belts, they will all be praying to Allah with outstretched hands the size of dinner plates while bleeding from ruptured eyeballs. Roller coasters are limited to about +5g for short duration in optimal seating conditions. The nearest such coaster to my location is the one in West Edmonton Mall.
Not to worry. I'm sure those powerful magnetic fields in evacuated tunnels are magically convex--at least on paper--after a little problem with the Swiss-made magnet contacts is sorted out.
If a train squeaks in an evacuated tunnel, does anyone hear it?
I had forgotten all about Canary Wharf. An ever popular business model: dream big, or go home. These kinds of projects never attract the feeble of heart.
Re:Simple (Score:5, Informative)
And don't tell me "it's different in Europe". I was in Germany. I can drive from Munich to Berlin faster than the ICE train. And the train ride costs $150+ each way per person.
Berlin-Munich costs 44 Euros each way (you have to buy the ticket a few weeks in advance though), and takes 6 hours. Driving takes the same amount of time, and will cost you at least 50 Euros in gas (600 km * 5l/100km * 1.65 Eu/l = 49.5 ~ and that's a pretty efficient vehicle - you won't get that efficiency doing 160 on the autobahn). So you're just plain wrong. Not to mention, many routes are much faster than a car; Frankfurt - Gottingen takes 1h40m on the ICE and 2h30m by car.
You can't look at the "in station" ticket prices, that's just ridiculous... have you looked at the price of airplane tickets if you buy them at the airport??
Swissmetro (Score:4, Informative)
A concept like this has be studied since 1970 in Switzerland. The subject was more warm in the early 1990, with an idea of real experimentation, but cooled down when faced the complexity of the project and his hazardous profitability. There is still some trace of it on the web:
http://en.wikipedia.org/wiki/Swissmetro
http://www.swissmetro.ch/en/home
Re:Liability (Score:5, Informative)
Won't be under an hour, unless we're pulling .2g or so.
More like 80-90 minutes.
Your point stands, however - it would make a bloody mint if it existed. If only from people who rode it just so they could say they did it....
Re:Liability (Score:5, Informative)
Well, in fairness, the Big Dig is not a good example considering that 2/3 of the money probably ended up in the hands of criminal syndicates of one sort or another. Also, it was built underground below the water table, and required a tunnel six or eight lanes wide - probably an order of magnitude or two more difficult and expensive than a train-size tunnel.
By comparison the City of Portland, Oregon recently completed the 'Big Pipe' [portlandonline.com] projects, digging about 10 miles of tunnel up to 160 feet underground (and under a river) to handle storm runoff. They used 14-foot diameter boring machines and did the whole project for $1.5 billion, which is about $150 million per mile. That cost included all the pumping stations and other costs, not just boring the hole. (See also West Side CSO Tunnel [wikipedia.org].)
So the cost of drilling a train tunnel, which would fit nicely in a 14 foot diameter tunnel, should be of the same order. Adding maglev or whatnot to make trains actually go would be additional, of course. At $150 million per mile, the 400 miles from SF to LA could be drilled for $60 billion. But you actually need three tunnels - one each way plus a service tunnel (like the Chunnel between UK and France), so call it $180 billion.
Re:Maybe because... (Score:4, Informative)
To put that in perspective, the first notable "flying machine" was invented 50 years after that. Yet we managed to put a man on the moon 69 years after, and 100 years after the sky is filled with airplane carrying passenger with safety record that rival all the other type of transportation.
Re:Liability (Score:4, Informative)
The problem we have in the US with high speed trains is our rail system is beat to crap by freight trains, meaning our trains can't go very fast. Other countries tend to use new and separate facilities for passenger and freight. Even Amtrak is starting to gear up for high speed rail [inhabitat.com], but it is dependent on private railroads for track. But laying new track, or improving existing track is far cheaper than building tubes all over the country.
Yet another example of how politics can ruin anything. In order to get the law creating Amtrak through, the politicians agreed to allow the railroads to continue to prioritize their profitable freight over Amtrak. Amtrak trains, except in a few cases, get the lowest priority of anything on the track. And Amtrak has no ability to improve track so their trains can go faster. In many areas they are restricted to 20 MPH due to track conditions, hills, urban conflict, etc.
The right way to do it would have been to nationalize the railbeds (buy them from the railroads) and let the railroads, now stripped to their essential function, compete on service and price. This could have been done back when the railroads were all going bankrupt. Now it's too late. Governments are reasonably good at maintaining infrastructure, businesses are generally better at service, so it would have been a productive arrangement, similar to both airlines vs. airports and trucks vs. highways.
Re:Why? (Score:4, Informative)
one word: VACUUM.
Two words: fire triangle
Two words containing a difficult one: fire tetrahedron
Before one will burst into flames one needs oxygen first. In a vacuum there is no hazard of bursting into flames. Remember this, and when you get your first physics lesson on combustion at school you will be mister smartypants!
If there is no oxygen, how on earth do you think the occupants of that vehicle are going to breath? You bet that such a train will need to carry oxygen, one way or the other. And in the event of a crash, that oxygen could be released into the vacuum, and there is your fire triangle, complete.
Re:Liability (Score:4, Informative)
Plus, if it was more convenient and also faster than air travel, more people would use it. One hour from LA to NY would take about the same time as my regular commute into work from the suburbs into the city (a distance of roughly 25 kilometres, in traffic).
Re:Why? (Score:4, Informative)
Re:Liability (Score:5, Informative)
You don't have to guess about the maglev part, because Japan is building an actual long-distance maglev line [wikipedia.org]. Costs seem to be about $200 million / km, but that includes everything, stations, etc (compare the various route choices and note that the construction costs don't vary nearly as much as the distances [that's affected by the amount of tunneling, etc, too, of course]).
Re:Simple (Score:5, Informative)
When folks talk about Amtrak, one of the first comments is that it is subsidized. It is, to the tune of 2.6B a year at the current moment.
We spend approximately $150B a year in state and federal money on highway construction and maintenance.
We spend approximately $16B a year operating the FAA and airports, about 3.5B of which is directly spent on facilities construction and maintenance.
All transportation is subsidized. Cost per passenger mile, cost per trip, or other similar metrics are a far better measurement of financial performance. Passenger fairs are also a very interesting thing to look at, if the same subsidy for rail and airports resulted in fares that were 50% less for rail travelers that may be a better subsidy.
The problem in the US with rail is really simple to boil down. Congress mandates Amtrak serve underserved and out of the way communities. Greenwood Mississippi has Amtrak service because the government said they must go there, not because it is the best route, or the most profitable one. At the same time Congress wants Amtrak to be profitable. That's a combo that doesn't work. It could be a profitable service by aligning routes with where people wanted to go, and dumping unprofitable ones. It could serve underserved communities with a subsidy. It can't do both at the same time.
High speed rail is a long term investment problem in the US, and a problem of our red-tape with building things. The transcontinental railroad was built in 6 years, largely with hand labor. California's high speed line is estimated to connect San Francisco to LA by 2030, 18 years from now. Much of this is the ever evil "regulation", however much of that derided regulation is stuff the people voted for in the first place so we don't destroy our environment, and so on. Much of it is time taken up with legal challenges, large and small, wasting time and money in court. We have to take a hard look at this sort of problem, the US is now building infrastructure at a much slower rate than most other western countries, and that's not a way to stay ahead. We can't just throw out the regulations, that will not leave a functioning society, but we need to streamline many of these processes.
Trains can work just fine in the US, and they do in fact operate profitably in several locations today.