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."
Why? (Score:1, Interesting)
Liability (Score:5, Interesting)
Re:Liability (Score:5, Interesting)
Airlines?
Re:Liability (Score:5, Interesting)
You're not any more dead than if your airliner falls out of the sky at 500 mph.
Safety is not the real problem. If you really put some research and development into it, you could probably get maglev down to $500,000 per km and probably a similar amount (if not more) for the vacuum tube (compare to $100 million per km right now). Then there's the cost of the trains, running the lines, maintaining vacuum ect. And for any run to make sense it's going to need to be thousands of km long, and every stop you make is going to defeat the purpose so direct lines between major cities are a must. A run from NY to LA would run you several billion dollars just to get started and several hundred million every year after that for maintenance and repair. So, the real question is: is there enough traffic between NY and LA (for example) to recuperate the cost of construction and operations. I highly, highly doubt the answer is yes.
Re:Simple (Score:5, Interesting)
Re:Simple (Score:2, Interesting)
For moving people around, this is a useless concept. But why not use it for cargo? That significantly reduces the risk and complexity of the "train" itself.
If you have to choose between an expensive train and a cheap track, or a really expensive track and a cheap train, which is better? I guess it depends on their relative expense. But, I expect that these days, the cost of the trains themselves is almost negligible compared to the expense of running the tracks.
Re:The only answer for the USA (Score:5, Interesting)
*So every Friday, four GS guys who always sat in the same spot, would have beers on the train. One of the guys retired, and they need a fourth to occupy the seats -- they didn't want some random person sitting with them. They asked me to sit with them, it lasted about two months until circumstances made it better for me to commute by bus instead of train. These guys would pound a beer (or two) in Penn Station waiting for their train, then drink another one (or two) on the 40-minute train ride home... they jokingly said it was the ammunition they needed to deal with their wives for an entire weekend.
But I digress...
If you take the Morris & Essex express into Hoboken or NY, which skips all or almost all the stops in Essex county, you'd believe that it's only the *wealthy* who take trains.
Re:Simple (Score:5, Interesting)
First, airlocks used in space are used a few dozen times at most before being completely overhauled. The docking connector on a train like this would get more than that much use in a single day, probably in a single morning.
If you're thinking of airlocks, then you'd have to depressurise and repressurise the train at every station. If you actually mean a tube connected to equal pressures outside of the tube and inside the train, then you're assuming that the seal of something that can be attached and detached, can handle one side moving as the train bounces up and down slightly as people step on and off, and still will have zero leakage.
It's a no-go (Score:4, Interesting)
I thought of the idea a while back, and I'm sure plenty of other people have too. It's really cool in a way, but I doubt it would ever be practical. The main problems I thought of:
Cost. It would have to be ungodly expensive by any measure, both to build and to operate. Could there ever be enough people willing to pay enough money to get, say, from NY to LA, faster than anything else to justify it? And it isn't very flexible either compared to air travel. If some other part of, say, NY, gets much more popular, then you can just build a new airport and reroute flights as needed. If you're using these giant vacuum tubes, you'd have to re-drill half of the run.
How tough it is to keep the tube in vacuum? We don't have any good way to estimate that now. Might need several high-grade vacuum pumps per mile that draw lots of power. It's pretty single-point-of-failure too - any significant air leak anywhere on the entire run, and any trains going fast enough to make such a system worth the trouble would probably be completely destroyed. It isn't just an air-resistance problem - unless the tube is much, much bigger than the train, then all of that air would be forced through the relatively small area between the train and the tube, thus much higher pressure spikes that would probably compromise any structure, and once you get the first crack, the whole thing will disintegrate real quick under the 6k MPH winds, leaving everything and everyone in the train as a stain on the walls over the course of a few hundred miles.
Handling sounds tough too. Like loading, unloading, servicing, turning them around, etc. You'd need lots of really good pressure seals that will stand up to many thousands of cycles with passengers doing all sorts of wacky things to them, and lots of elaborate procedures carefully followed. Getting trains into pressure for service (or do we have service techs in space suits?), loading and unloading passengers and cargo though some kind of airlock/jetbridge thing. Make a mistake anywhere, and you either pressurize the tube, destroying any trains travelling in it at the time, or suffocate all of the passengers in a train. Hope you never have a train break down in the middle of the line either.
Re:Simple (Score:3, Interesting)
You're assuming that there is no other way to spend the money on infrastructure that would have more benefits. How about adding a dozen more regional airports? Same effect, only doesn't cost tax payers on an ongoing basis.
Re:Simple (Score:4, Interesting)
You do realize that this article is about _trains_, right? You and your monomania are what brought space into the discussion. There's nothing impossible about a maglev train, nor a superconducting power cable, nor a depressurized tunnel. We already have all of these things. It may prove cost prohibitive to operate a train system like this.
Frankly, all that the article could really has to say about why such trains aren't being built is that they might be hard to maintain and everyone will die if it crashes. That and some completely hyperbolic speculation about one little leak almost immediately compromising the entire vacuum. So, basically, wow. Super-informative article. No really.
Re:Liability (Score:4, Interesting)
I dunno - considering the level of catastrophe that happens to vehicles going 4000 miles through air when a paint chip strikes them, making a vehicle that operates a minuscule fraction of a millimeter from walls going by at that speed without turning into molten slag seems pretty difficult. I can argue that it _might_ be possible to extend our present knowledge and technology to build a 550 MPH (800 KMH?) vehicle that could survive most minor events - I would think that making derailment impossible would be one useful approach. But at 4000 MPH even a bump a millimeter high - anywhere on the hundreds of miles of wall - would be beyond fatal as any minor removal of material would cause the removed material to propagate and become a storm of removed material.
I will note that many stores still have very useful vacuum-based paperwork distribution systems to ship receipts or something from checkstands to the central office. So vacuum systems do work - I just think 4000 MPH is beyond fantasy.
Re:Simple (Score:4, Interesting)
If there were no one daydreaming about the possibilities, no one would attempt the impossible. Thus it seems to me that the starship Enterprise is a necessary step towards achieving the space shuttle Enterprise, even as the space shuttle Enterprise is merely a rung on the evolutionary ladder to the starship Enterprise (there's a recursive conundrum for you, lol!).
Furthermore, compared to a lot of the other attempts at powered, manned, heavier-than-air flight, the Wrights followed a much more rigorous, evolutionary process towards their goals, which is one of the biggest differences between them and their predecessors (as well as many of their contemporaries). However, if you think that they threw out all of the thinking about flight that came before them, you are very much mistaken. Man had flown before Wilbur and Orville, even in heavier-than-air aircraft. Google Otto Lilienthal for an example (hint: what's the biggest, most obvious difference between a Cessna and a Blanik?). The Wrights took the collected knowledge of their day, tested numerous theories, and, as you said, "threw out all the junk" -- but they KEPT a lot of things, too. They had two big breakthroughs that had eluded others: first, they understood that for powered, sustained flight, you don't want the aircraft to be too stable because stable and controllable are diametrically opposed; second, they understood that turning an aircraft required redirecting part of the lift vector in a horizontal direction (i.e., turning requires banking rather than yawing). Basically, they were *excellent* examples of putting the scientific method into practice: observe, hypothesize, test, wash, rinse, repeat, and then take the one additional step that separates a scientist from an inventor, namely, build a practical device that makes use of the results of experimentation.
No, "Eureka!" doesn't happen from simply staring at your navel, but then again, I don't remember claiming otherwise. I merely pointed out that oftentimes, "Eureka!" is the result of approaching a problem from a different perspective. The "insurmountable" obstacles often aren't. They just require technology or knowledge that didn't exist earlier (wing warping, unstable airframes, and strong-enough-but-light-enough powerplants, in the Wright Brothers example or understanding that it is the equal and opposite reaction rather than exhaust gases pushing against the atmosphere in the rocket-in-a-vacuum example I mentioned earlier).
Re:Simple (Score:4, Interesting)
For example, you seem to have a pet peeve about ever colonizing space. I agree that with our current state-of-the-art, it won't happen. Chemical rockets can't achieve the kinds of velocities that are necessary to cross the vast distances between earth and even the nearest of stars (excluding the sun, of course). Einstein predicted that even an infinitely powerful engine wouldn't even be able to do so, due to the limiting factor of c. Consequently, yep, the outlook for colonizing space looks pretty bleak from here at the beginning of the 21st century. But neither you nor I know what kind of breakthroughs in physics are going to happen in the next hundred, thousand or even ten thousand years, any more than a Roman Centurion could have imagined the Internet or nuclear fission. It's probably safe to say that there won't be a physics breakthrough that allows us to actually accelerate a mass faster than the speed of light...but is there a way to avoid that limitation altogether? Will we figure something out that lets us sidestep the speed of light as a limiting factor? We don't know. Therefore, I take exception when people like yourself say something like space travel will "never" be possible. Never, as I am fond of telling my daughter, is a really long time. It's certainly a lot longer into the future than you or I will ever be able to see.
Re:Simple (Score:4, Interesting)
Trains do not work in the US because of what the US is.
Europeans always forget how incredibly tiny their nations are and how incredibly big the US is. Our population isn't bunched up into a few mega cities like yours is either and there is no reason it should have to be. Some people consider privacy to be more important than the infrastructure advantages in everyone being close together.
Suppose you built a high speed rail between LA and New York. Its fast, 200mph. So it can (ideally) cross the 2378.8 miles in a little under 12hrs if it makes no stops. Wonderful, its faster than I could drive it. But how now that I'm in new york, how do I get to the store that is 5 miles away from the station? Now that I am there, how do I get the shopping cart full of goods back to the train? Do I purchase another couple seats to store it? Will the train wait while I load and unload it? How do I get it to my home in a small town 50 miles from the station? What if my purchase included a piece of plywood and four 3m lengths of pvc for some basic work around the house? And if like many I do that every 3 days?
In the EU you might be considered extremely rural if you live 100km from the nearest reasonable point for a passenger station but it would be considered the suburbs here in the US. You'd have to go quite a bit further to reach rural.
Re:Liability (Score:5, Interesting)
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....
I'm not sure I buy that: Round-trip flights between LA and New York can be had for under $300 and take 7-8 hours, including time at the airport. So what price premium is the public willing to pay to get there in 1/3 the time (assuming it takes some time to get on and off the train)? I have trouble believing the capital costs of a vacu-mag-lev passing through two mountain ranges is going to have a lower per-mile cost than the current California HSR (currently ~$100 billion for ~500 miles, or $200 million / mile).
Do you think you can really charge a big enough price premium to cover the extra capital and operating costs of such a thing? I think the Concorde has your answer.