Pipeline Mass Transit? 557
pipingguy writes "'Evacuated Tube Transport (ETT) is a new kind of transportation system that requires less than two percent of the energy of current transportation methods. It is also much safer, and can be faster. [...] Anyone can visualize 2 tubes (one for each direction) along a travel route. Air is permanently removed from the tubes; so travel takes place without friction. Pressurized passenger capsules (like a 2 - 8 person airplane cabin), travel in the tubes on thin steel wheels or on nearly frictionless Maglev. Airlocks allow access without admitting air to the tubes. Linear motors (as used on new rollercoasters) accelerate the capsules. During most of the trip the capsules coast; using no power. When the capsules slow down, linear generators recover most of the electrical energy used to accelerate the capsules.' Some CG images and drawings here, the FAQ is here." MSNBC had an article on monorails a few days ago. Don't bother making Simpsons jokes, the article has them covered already.
But it's not open source... (Score:3, Informative)
Another thing about friction (Score:3, Informative)
don't mean to be a pessimist, but... (Score:5, Informative)
Not with the hundreds of miles of tube.
Not with termal expansion/contraction.
Not in an active city with people building, digging holes, running infrastructure.
Not in an even remotely seismic active area (remember the earthquake in NY?).
While its a cool idea, its just that, an idea. There's no way to overcome the problems and still make it as durable and cost less than existing technology.
Re:Another thing about friction (Score:5, Informative)
Finally, friction isn't the only source of energy loss in a rolling tire. In fact, as long as you aren't skidding, almost none of the energy is lost to friction (because rolling friction is really a special case of static friction and energy is lost in dynamic friction). Most of the energy in rolling a tire is lost continuously flexing (and heating) the tire sidewall under the weight of the vehicle.
Thin steel wheels deform a whole lot less than radials and will therefore lose less energy when rolling.
But Heinlein had the right idea. Dig the tunnels deeper and have them follow great circles through the crust. Then launch the cabs to orbital velocity (but inside the earth). No wheels. Or expensive magnets. Just a nice vacuum and a very fast ride. Of course, the acceleration/deceleration might be a bit brutal...
Regards,
Ross
Re:Um... (Score:3, Informative)
http://www.pbs.org/wgbh/amex/technology/nyundergro und/secret.html [pbs.org]
Re:I see some errors in this reasoning (Score:2, Informative)
Magnetic field strength falls off very quickly: "From single conductor sources, magnetic field strengths decrease directly proportional to the distance from the source (1/D). From multiple conductor sources, magnetic field strengths decrease as the square of the distance (1/D). And, from coils or loops, magnetic field strengths decrease as the cube of the distance (1/D)" (grabbed this quote here [fms-corp.com].)
Someone further down was talking about superconductors; while in theory much more energy efficient, there are none currently that don't require massive cooling systems to lower them to the necessary temperatures. The cost of laying out miles of superconductors below ground is mind-boggling.
A neodynium magnet is incredibly powerful for its size(I've managed to squash a thumb between two hard drive magnets while being stupid), but the field strength fall-off means that a huge mass would be required. It might even be cheaper to build a superconducting system after all.
Friction (Score:2, Informative)
If you take two sticks into space and rub 'em they're still going to wear against each other. No?
Robert Goddard proposed this in 1904 (Score:2, Informative)
Swissmetro (Score:4, Informative)
This has already been researched in Switzerland... (Score:3, Informative)
A quick summary of it here [laiwww.epfl.ch].
The most complete analysis of the project I've seen here [www.strc.ch].
Basically, it's probably doable, but the major roadblock is a VERY strong political support (even in a very pro-mass transit country like switzerland), because of the massive costs to validate the faisability of it. In Switzerland, that support has not materialized in the last 20 years.
Re:Doesn't make sense. (Score:3, Informative)
Not a bad way to do this calculation, if you don't have access to calculus and the like. Unfortunately, your answer is wrong, because the radius of the Earth is a touch under 7000 kilometers, not 13000 as you claim.
An easier way to do this would be to remember that the centripetal force required to keep an object with mass m moving in a circular orbit of radius r and speed v is just m*v^2/r. Equate that to the force of gravity at sea level and you have that:
v^2 = g*r
Just think of gravity as being the "string" that keeps the satellite in its circular path. At sea level, this works out to 8.3 km/sec or thereabouts. Incidentally, it can be shown that the minimum escape velocity is just this number multiplied by the square root of two.
Cheers,
Mouser
Re:From now on, we'll all travel in TUBES! (Score:2, Informative)
Re:From now on, we'll all travel in TUBES! (Score:4, Informative)
I knew several people who lived outside of London, as well - and only two of them had cars.
As a whole, Americans are too lazy to make public transportation viable. Unless you're in a big city, the only people who take the bus are people too poor to have a car - and since so few people use the buses, there is no incentive to a) have busses stop more often, or b) put stops closer together.
I couldn't even get a job this summer because I didn't have a car...
Re:From now on, we'll all travel in TUBES! (Score:5, Informative)
Maybe you should come to NY... I live in a small part of NYC (Staten Island) and even here there are buses that run 24/7. A bus usually comes every half hour all day. There's also a ferry that goes to manhatten (when people talk about NYC, they're usually talking about manhatten), from staten island, at least every hour (every 15 minutes during rush hour.) There's the metro north also, I can take a train to just about any place in the state of NY for a few dollars. The buses and subways cost $1.50 (the ferry is free and express buses are like coaches, comfy seats and stuff, they're $3.)
There's also this great little card called a metrocard. You can go to just about any deli or small store or whatever and pick one up. They usually have $15 metrocards, they work on buses and trains, when you get on the bus you just stick the card in the slot and get on, very quick and very easy. You can refill them too, much easier than carrying change or tokens. The trains have turnstyles so you just slide the card through and go through the turnstyle. You can also transfer from one thing to the next, like lets say you needed to take the S74 (S is for staten island, 74 is the route) to the ferry and needed to get onto the 1 train in manhatten, you just pay for the bus and on the metrocard you get a transfer (or you ask the driver for one if you payed with tokens or change) and you get onto the train for free.
What about leaks in the cars? (Score:3, Informative)
Imagine if two of these pressurized cars collide, and their seals break. All their air would escape into the tube, and any passengers that survived the impact would suffocate in a fairly gruesome Total-Recall-like manner.
The safety section of their FAQ doesn't even address this.
Shock tubes (Score:4, Informative)
They are talking about the fact that there will be SOME gas in the tube, not much, but it will be there.
Aerospace engineers have been doing this kind of problem in the lab for years, we call them shock tubes [aerodyn.org], you can also check google [google.com].
They are a Rambus company (Score:5, Informative)
From their site ("company summary" page)
Our aim is to generate returns for our shareholders by acting now to acquire control of important blocks of intellectual property (patents and trade secrets) in the ETT field. We currently own the patent and trade secret rights to Evacuated Tube Transport, the first practical evacuated tube transport technology. We believe that these ultra efficient and environmentally benign systems, will become key components of numerous future worldwide transport systems. ET3.COM INC. intends to take full advantage of the generic nature of this unique technology by securing the intellectual property rights on the lion's share of all specific applications, new devices, and novel systems issuing from it. Management also believes that we are well positioned to gain control of other major intellectual property by developing new patents and trade secrets through our own internal efforts and by developing patent-exploitation agreements for the patents and trade secrets belonging to others.