quote:

ORIGINAL: SL4V3M4YB3
 
The section of track lit up would have to be well in excess of the train length when you take into account the speed the training is running at, an acceptable safety margin and the need to spit the track into logical sections that can realistically be managed by a computer system.
With the high speed switching controls that are available today you would only need about one half the magnetic depth of the attracting magnet ... we are talking inches here.  Well inches in front and in back of the train and of course the length of the train.



All I want to know is why people think it matters if the train has wheels on or not. Surely the art of transport planning is knowing what places you need to connect based on demand. People can buy gimmicks if they like but I'd prefer tried and tested methods because whilst I can see the advantage of wheels over levitation I can't see the advantage of levitation over wheels. Also the braking system won't be exerting wear and tear on the track will it?
The advantage of levitation over wheels is that there is no friction thus no wear on the track or the train.

quote:

ORIGINAL: Hippiekinkster
See, if you actually knew anything, you'd know that mag-lev technology is based on a 1934 patent. Just this once I'll help you out, sparkplug.
http://en.wikipedia.org/wiki/Transrapid

Your ad hominems aren't very good. Keep trying, though.

quote:

ORIGINAL: SL4V3M4YB3

quote:

ORIGINAL: Hippiekinkster
See, if you actually knew anything, you'd know that mag-lev technology is based on a 1934 patent. Just this once I'll help you out, sparkplug.
http://en.wikipedia.org/wiki/Transrapid

Your ad hominems aren't very good. Keep trying, though.

Yes but how long has a working model been around for sparkplug? Also how does this support your case that maglev is the better alternative to proven methods?
One might also have asked that same question to the inventor of the wheel.

All you've done thus far is say I can't have a clue about anything transport related because I'm 29.
I think it is possible that his opinion is based less on your age than on the fact that you do not seem too interested in discussing the technology.  Several links have been posted to sites which discuss not only the viability of maglev but also the basic technology.  All of which you seem to disregard as being too unimportant to even read.
Maglev is a 70+ year old technology which has several working models and extensive testing performed.  All that is currently lacking is funding and a will to proceed.  You are obviously a bright fellow why not take a look at the cites provided and give us your opinion instead of just dismissing the whole concept out of hand.

quote:

ORIGINAL: Hippiekinkster

That's not the problem. The problem is, the power required to overcome drag is the cube of velocity ( http://en.wikipedia.org/wiki/Drag_(physics ) (1st derivative of speed)
Yes I agree that trying for 6400kph at atmospheric is not doable.  If we could create a vacuum or even a partial vacuum inside the tube this problem would go away.  Of course the other side is why the need for 6400kph.  I could certainly live with subsonic speed.  I am not sure there is a cost benefit to the higher speed.

( http://en.wikipedia.org/wiki/Derivative)
At ~~6400kph, that's one hell of a lot of drag to overcome. Then you have the shear stress (friction, basically http://en.wikipedia.org/wiki/Shear_stress ) between the carriage and the guideway. Then you have the force directly acting on the front of the train.
I am a little out of my element here but I thought one of the main advantages of maglev was that the vehicle was suspended in the magnetic field so there should be no shear forces generated.


You wouldn't have 10 atm (more like 11.5 @150 ft., if 1 atm/13 ft. is correct)(hell if I know, I use ISO units. Inches, feet, Fahrenheit, all that is so primitive)  (I use pascals or Torr for pressure) inside the tube, just outside. Inside, unevacuated, would be approx. 1 atm (760 Torr). Think about why this is true.
One atmosphere is 33' or about 10m.  Three hundred feet would be about ten atmospheres and one fifty would be about five.  One atmosphere is about 15psi.

If you figure the water temp at depth is about 0C, an unevacuted, unheated tube would also be 0C. This is of minor relevance, but that small differential does add some heat transfer.
Seawater temp at 300' is in the 40 degree f range...you don't get down to the freezing point till you get below about a thousand feet.
Here's a NASA paper on skin temp at high velocities:
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930088771_1993088771.pdf
which show max temps at high Mach numbers.
Then it's a matter of materials science; titanium would be more that adequate to build the fuselage of the carriages from.

So you can see, the basic problem is drag. Ask our little English transportation engineer.

Yes I agree that if you want to get to the higher mach numbers the tube will have to be evacuated otherwise drag as a function of the cube of velocity will form the upper speed limit.
My point was that at depths of five to ten atmospheres we have the pressure of the water for free.  If we could harness that pressure to depressurize the tube then virtually any mach number would be attainable since the vehicle would be traveling in a vacuum or at least a partial vacuum.

quote:

ORIGINAL: kittinSol

I've done the Eurostar more times than I remember; I used to travel by train all the time. Until...

Why aren't there more trains in America? It's the perfect country for it. Tons of space for railtracks, and I'm sure the infrastructure's all there. Why  ?

quote:

ORIGINAL: thompsonx
The advantage of levitation over wheels is that there is no friction thus no wear on the track or the train.

quote:

ORIGINAL: SL4V3M4YB3

quote:

ORIGINAL: thompsonx
The advantage of levitation over wheels is that there is no friction thus no wear on the track or the train.

Problems with maglev:

The ability of maglev to carry freight?
Why would maglev have any problem carrying freight. 
 
Going up or down a hill is hard, therefore we need to build viaducts everywhere to keep things level, therefore planning permission problems.
Actually maglev goes up and down hills easier than conventional wheels and rails because it does not rely on friction for traction.  Traditional rail is limited to a 6% grade.
 
 
Complex junctions with every one being a major installation rather than a simple device that bends steel rails.
I do believe you are mistaken here.  The junctions would actually be less complex since they would be electronic and not mechanical and thus would not be subject to wear.
 
 
Although there is no frictional resistance wear and tear is obviously still exerted on the track structure through dynamic loading.
How would the dynamic loading of a maglev train differ from a conventional one?  Same dynamic load no friction wear would seem to indicate less maintenance.
 
 
Specialist engineers required to service the track at unsociable hours.
It would seem that these would be the same sort of complaints that would have been leveled against air traffic...Really engineers are engineers and parts is parts.
 
Specialist components imported from overseas because the world leader in maglev technology isn't the USA.
Are you suggesting that Americans are not bright enough to make parts....
 
I'd like to see a power consumption comparison with like for like networks.
I would like to have sex with Pammie Anderson. 
It strikes me that you are trying to pick fly shit out of pepper.
Do you really suppose that the power to move a frictionless item is going to be more than it takes to move something that uses traction as a means of propulsion.
 
Problems with wheels:

Frictional forces lead to wear and tear, oh dear.

The real question is what is the fascination, when a traditional system can perform just as well and be serviced in a more simplistic way? Quality is fitness for purpose and I've yet to see anyone demonstrate a maglev system that can outperform traditional rail in any aspect other than gimmickry.
I can only assume that is because you refuse to look.  Google is your friend.

It's your tax dollars however.
Actually it is all of our tax dollars.  Just as it was all of our tax dollars that took us to outer space and Iraq.

quote:

ORIGINAL: Hippiekinkster

Thompson, I said 0C. I don't actually know the temp at 150 ft. at higher latitudes; I do know that salinity depresses the freezing point. Some parts of the ocean are below 0C (32F).
Yes I understood your reference to 0c.  Ocean water at the depths we are talking about (50m to 100m) tends to be in the 40f range.  You need to get below the 300m range before it starts getting into the 0c range.

You are correct about the water pressure. For some reason, I had 13 feet in my head. Why? Who knows? Should've calculated it.
Yeah I get brain farts like that too...I knew what you meant though.

Anyway, the Trans Rapid system has a gap of 1cm between the carriage and the guideway. Air is consided a fluid for the purposes of shear calculations.
"
Yes,I understand.

A viscous fluid (including air and water) moving along a solid boundary will incur a shear stress on that boundary. The no-slip condition dictates that the speed of the fluid at the boundary (relative to the boundary) is 0, but at some height from the boundary the flow speed must equal that of the fluid. The region between these two points is aptly named the boundary layer. The shear stress is imparted onto the boundary as a result of this loss of velocity and can be expressed as

      " From the link I gave previously.


I am not unfamiliar with this.  My problem was that I misunderstood your use of the word shear.  I was thinking in terms of mechanics and not aerodynamics.
It should not be a problem at subsonic speeds.  At super sonic speeds it just seems to make the case for creating a vacuum.
 

quote:

ORIGINAL: Moloch

Most American Rail rines were regulated out of buisness. Bigges revenue for rail roads is freight hauling so mag lev would be a waste of money.

quote:

ORIGINAL: luckydog1

Sure you could design and build a super complex super speed maglev train,
I am curious as to how you arrived at the conclusion that an electro-magnet is a more complex device than a jet engine or even an internal combustion engine.

that luanches cars near the speed of sound, 
The speed of sound at anyplace a train would be is over 700 mph.  We have been discussing speeds in the 300 to 500 mph range.


Into a vacume tube,
Vacuum tube???  The possibility of using an enclosed track (tube) with a reduced pressure for speeds in the 4000mph range under the ocean was discussed but not putting trains in vacuum tubes.




connects to the front of the train, then the people move to the proper car to be dropped off at thier destination (supposedly thier lugage will also?). 

It would appear that in your haste to disagree with me that you failed to recognize two different concepts that were being discussed.
One a high speed commuter train and the other a hyper speed trans-oceanic train.

All synchronised in a giant system with trains moving down tracks at near the speed of sound.  And when it works perfectly, get a similar speed of travell to flying.
At a fraction of the cost of air travel and without the attendant problems of air travel...ie:noise pollution,enormous land requirements,limited lifespan of aircraft etc.


OF course that assumes that the entire system functions perfectly.  Simply to move the lugage would require some sort of automated machine, sort of like at the Denver Airport.  Which of course functions flawlessly. 
Are you suggesting that human ingenuity is not capable of solving mechanical problems.
Why do you pick DIA's problem plagued system as an example of baggage handling?
How does DIA baggage handling compare with JFK or LAX.
Looks to me like you are just trying to pick fly shit out of pepper.

You can't put a Train going the Speed of sound into a holding patern.
Why would you want to?
 
And you can't stop on a track with stuff going that fast, unless you stop everything.
This has already been explained in the previous posts...you do not need to stop the train so why do you continue to bring this non issue up?

The delays and problems with a system like this would be enourmous, even though it is technically feasable.

We already have a system of fast transport,Airplanes, and trains for hualing freight.  And a system of slow transport trains cars and buses.  It can take people from door to door.  Why would we need to spend trillions of dollars to build a giant Maglev system?  What benefit would it have, besides being cool?  Which on a scale of 1-10 is an 11.  Its super cool.  We could spend the money on a lot of other real needs. 
Perhaps you missed some of the posts.  You might want to go back and reread the thread.  It is not about the "cool factor"  It is about being safer,cheaper and faster.

quote:

ORIGINAL: luckydog1

Doe anyone have a real comparison of power usage on these things? 
Perhaps you might take the lead here and find out on your own instead of asking others to do your legwork.

They use electricity and are silent which is nice.  But how much electrcity do they use?  My reading between the lines abilities makes me think if it were a better use of power, it would trumpeted all over the related web sites, and it doens't seem to be. 
Perhaps your vaunted ability to read what is not there is flawed.

How much gets lost in transmission to the rail?  If you are using dirty electrcity to run the thng, it might be greener to use a natural gas fired regular train.
Or a natural gas fired electrical power generating plant.

It's safe to say that solar panels on the cars won't levitate a train,
Since you have already confessed your ignorance in this area how can you make this statement?

much less make it go at sonic speeds. 
You seem to be the only one carping on sonic speed.  Most of the post have been discussing speeds in the 300 to 500 mph range.

 In a way, this could end up running the trains on coal again, as thats where most American electrcity comes from.


The one in China almost certainly runs on Coal. 
The answer is but a keystroke away yet you guess.  Why is that?
 
Germany's is Nuclear I would guess, but am not sure about that.
Again you are but a short step to google away from knowledge instead of guessing.

Also how much power does it take to make the superconductors/ drive drain?  I imagine that it is a rather ungreen process.  But how does it compare to the making of a regualar train?
All it would take is a few minutes with your old friend google to find out.

his stuff is fascinating.

quote:

ORIGINAL: luckydog1

And there is no reason to move freight super fast.
I guess that is why we still use ox carts to move cargo.


Cargo that needs to be flown fast can be shiped by air.  Flashing ambulance to airport, planes diverted and imediate takeoff, cleared airspace, waiting helicopter to immediatly fly to the destination, through cleared air space,--when it is life or death fast. 
In real life this does not happen so why do you act as if it does?



Trains could never accomadate that.  You can't clear the tracks and send a super express through on short notice.There is absolutly no reason to have train loads of Iorn ore moving at the speed of sound. 
Speed of sound?  Most of the post seem to indicate that speeds in the 300 to 500 mph range were what is being suggested not the speed of sound which is over 700mph at any altitude that a train might be operating at.

And you would have to have seperate sets of tracks to have super fast never stopping trains and huge lunkers with hundreds of box cars of Ore, cattle, grain, or Boxes of durable goods.
Only in the scenario that you propose not the one that has been suggested


It's kind of wierd listening to people say there are no trains in the USA.  I have over 6000 miles from coast to coast riding them.

quote:

ORIGINAL: thompsonx

quote:

ORIGINAL: Moloch

Most American Rail rines were regulated out of buisness. Bigges revenue for rail roads is freight hauling so mag lev would be a waste of money.

Which regulations put which railroad out of business?
Why would hauling freight with a mag lev be a waste of money?
thompson

quote:

ORIGINAL: thompsonx

quote:

ORIGINAL: luckydog1

And there is no reason to move freight super fast.
I guess that is why we still use ox carts to move cargo.
We don't, is sarcasm the only response you have?  why would we need to move ore and heavy goods around at high speed?  What benefit is there?  You are admitting there is none by responding with an absurd snark.  You responded, but have no real answer.


Cargo that needs to be flown fast can be shiped by air.  Flashing ambulance to airport, planes diverted and imediate takeoff, cleared airspace, waiting helicopter to immediatly fly to the destination, through cleared air space,--when it is life or death fast. 
In real life this does not happen so why do you act as if it does?
There are Medivac flights on a regular basis, adn they happen exactly as I described.  The scenario I described happens a few times a week in my state, and the rest of the country also. 



Trains could never accomadate that.  You can't clear the tracks and send a super express through on short notice.There is absolutly no reason to have train loads of Iorn ore moving at the speed of sound. 
Speed of sound?  Most of the post seem to indicate that speeds in the 300 to 500 mph range were what is being suggested not the speed of sound which is over 700mph at any altitude that a train might be operating at.
Ok I started off with the 300 MPH speed which you objected to, What speed do you want to use?

And you would have to have seperate sets of tracks to have super fast never stopping trains and huge lunkers with hundreds of box cars of Ore, cattle, grain, or Boxes of durable goods.
Only in the scenario that you propose not the one that has been suggested
??  Where would you put the current hundreds of millions of tons of heavy good presently shipped by train, except on the system you proposed, to eliminate all the current rail system  replacing all the tracks with maglev?  Why would you want to spend the energy to levitate ore and make it go 3-500 MHP.


It's kind of wierd listening to people say there are no trains in the USA.  I have over 6000 miles from coast to coast riding them.