carnej1 NASA, the US DOT and other entities have done R&D but nobody has a secret plan to roll out a vactrain network in the next 2 years..
NASA, the US DOT and other entities have done R&D but nobody has a secret plan to roll out a vactrain network in the next 2 years..
Um, China in the next 10 years?
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
Good for China. They can waste the money and figure out that its a hilarious, unworkable disaster.
erikem Paul Milenkovic Dad's explanation is that an elliptical orbit cutting through the Earth takes 80 minutes for a round trip (OK, so a more precise number is 84 minutes then), so the one-way trip time would be 42 minutes then. But don't forget the 4 hours for clearing security on departure, immigration and customs on arrival, local ground transportation on each end, making the trip 4 hours and 42 minutes. I seem to recall that 84 minutes was also the period of a pendulum with a length equal to the earth's radius, this time period coming up in the alignment of Inertial navigation systems. I do recall that the travel time was the same for any route. But maybe 84 minutes is the correct time if you are doing a practical ultra-high-speed vacuum-tunnel train rather than a straight-line free-fall route. But you still need to add 4 hours to that figure. 42 minutes may very well be the travel time, I'm not making any claims about my memory being infallible.
Paul Milenkovic Dad's explanation is that an elliptical orbit cutting through the Earth takes 80 minutes for a round trip (OK, so a more precise number is 84 minutes then), so the one-way trip time would be 42 minutes then. But don't forget the 4 hours for clearing security on departure, immigration and customs on arrival, local ground transportation on each end, making the trip 4 hours and 42 minutes.
Dad's explanation is that an elliptical orbit cutting through the Earth takes 80 minutes for a round trip (OK, so a more precise number is 84 minutes then), so the one-way trip time would be 42 minutes then. But don't forget the 4 hours for clearing security on departure, immigration and customs on arrival, local ground transportation on each end, making the trip 4 hours and 42 minutes.
I seem to recall that 84 minutes was also the period of a pendulum with a length equal to the earth's radius, this time period coming up in the alignment of Inertial navigation systems. I do recall that the travel time was the same for any route.
But maybe 84 minutes is the correct time if you are doing a practical ultra-high-speed vacuum-tunnel train rather than a straight-line free-fall route. But you still need to add 4 hours to that figure.
42 minutes may very well be the travel time, I'm not making any claims about my memory being infallible.
Semiballistic max time is about 54 minutes. You 'physicists' seem to be forgetting your great-circle navigation; the furthest-removed destination being only one-half a great circle (otherwise you'd just go the other way) and the effective flightpath being only slightly longer.
Intercontinental tube trains are an expensive, geologically-unsound answer to a question nobody has asked. I would recommend that discussion stick to established 'destination pairs' for which the traffic is cost-effective relative to the expenses. Any thought of orbital speed -- and I haven't seen anyone indicate just what they think the speed for an 84-minute orbit actually is, although it is well-established -- in a tube on the ground goes beyond fantasy into the realm of active danger and ethical stupidity. In my opinion. For what it's worth.
RME
Firelock76sambard Kingdom Brunel came up with a vacuum propelled railway in the 1850's. That was a bust as rats and mice had a bad habit of eating the greased leather flaps that sealed the system. I believe the French tried the same system and had the same critter problems. C'est la vie!
Wayne,
How can you suggest that I fail to understand vacuum tube railways, an idea that has been around since at least 1850? I mean what is so hard about constructing an underground tube similar to those now used in banks but big enough for people to ride in, exhausting the air in that tube, putting people in a compartment similar to the ones that banks use at openings in the tube and zipping them off to where ever they want to go?
Although there need not be an actual train of cars and banks use single containers, not trains of them clearly this is similar to a railroad train. Of course for it to run on rails the rails also would have to be sealed.
And as you point our, Isembard Kingdom Brunel had it all down pat and we need only to follow his plans but replace the leather seals with rubber ones or a kind that will not attract mice. (Actually a field mouse did eat his way through a rubber seal at the bottom of my garage door. I think this gives me special experience to be on the design team).
I am organizing a company to set up a vacutrain. This is a sure thing. And I am giving you the opportunity to get in on the ground floor. Even a small investment would make you rich. Tell me how much you want to put in to the company.
John
Paul Milenkovic carnej1 NASA, the US DOT and other entities have done R&D but nobody has a secret plan to roll out a vactrain network in the next 2 years.. Um, China in the next 10 years?
Is that a prediction or can you cite an actual,funded program?
"I Often Dream of Trains"-From the Album of the Same Name by Robyn Hitchcock
Note: assume absence of whooooosh factor in what follows.
Firelock76sambard Kingdom Brunel came up with a vacuum propelled railway in the 1850's. That was a bust as rats and mice had a bad habit of eating the greased leather flaps that sealed the system.
Far more to the relative 'failure' of Brunel's vacuum traction than the leather flaps, or other 'likely' sources of animal interference. It's difficult to keep the vacuum piston and head aligned with the tube while the vehicle is negotiating a very different profile of track. Switches are... well, let's just say 'not very cost effective'. And then we come to the requirements for the pumping plant(s), and accumulators instead of reservoirs, and the size of piston needed to propel more than a couple of waggon-loads of freight with less than an atmosphere of effective pressure to do the job...
John WR How can you suggest that I fail to understand vacuum tube railways, an idea that has been around since at least 1850? I mean what is so hard about constructing an underground tube similar to those now used in banks but big enough for people to ride in, exhausting the air in that tube, putting people in a compartment similar to the ones that banks use at openings in the tube and zipping them off to where ever they want to go?
Well, how long a list do you want about why it's hard to BUILD, as opposed to imagine? (Note: John, this is not for you, it's for the people who initialized this thread.)
There is a very large difference between sending a 4" diameter carrier a few blocks and sending a train continental distances, presumably with gravitational acceleration. Even if the telpher system uses full vacuum and no air boost behind.
The chief stupidity with the gravity vacuum trains is the presumption that you can put a straight, vacuum-tight tube through a large stretch of the lower mantle, and at each end through moving plates. Were you going to use scrith? What were you going to use to hold the bore open before lining it? It's little details like these that make the idea somewhat harder to translate into engineering possibility... we won't take up economic practicality, or even due regard for human safety, until later.
Let's take the 'exhausting the air from that tube' as an example. Just exactly how much air are you talking about, and what kind of pumps were you going to use? (I presume you are aware that the expressed volume per time of pump operation goes down with the pressure...) And while we're at it: a 'normal' vacuum transport system will pump from multiple ports. You're going to put those where? And exhaust them to where? Now compare that pumping power with, well, traction power for HSR, or energy to run methane liquefication plants for semiballistic aircraft. How did that old AT&T commercial go -- 'where's my big savings?' The 'free' gravitational acceleration looks like less of a bargain.
Now let's investigate what happens behind the train -- any train -- that accelerates into the now-presumably-well-enough-evacuated tube. Hint: Gravity is not straight down at the tube entrance, so you will need some motor action ... probably LIM with long fixed stators in sections... to get reasonable trip time. What fun if the LIM at the other end fails to deploy with correct timing and phase! ... something you are highly likely to discover only at actual deceleration time? You can flood the tube with air, but that's likely to leave the train far down in the tunnel, if indeed not actively rebounding down the hole... so for any accident, you either need a self-propelled tug that can connect to the train to pull it out of... where it has slid by the time you get there... or you need to put a passive LIM "rotor" in the tube structure all the way. Which would be fine, except you will assuredly get to the Curie point for your LIM material at a comparatively short distance into the tunnel, and I would suspect higher temperature excursion... unless, hey! I know! let's put heat pipes down the walls to keep the temperature in the bore equalized! How long did you say that tunnel was going to be? ...
I have not even had to get to the fun if there is even a comparatively small leak in the train pressurization. Oxygen masks dropping from the overhead will NOT address the significant problems this will cause for the passengers. To give you a transit analogy, think Malbone Street, but this time with no survivors. Will your company be better capitalized than the Brooklyn system was? sure hope so!
Of course for it to run on rails the rails also would have to be sealed.
I strongly suspect that no rotating wheel-on-rail system will be dynamically stable at the peak speed this thing needs to run -- have you, for example, calculated the peripheral speed of your wheel at max V? (That was a limiting factor on rotational speed for 8" hard drive technology, btw... the math gives interesting numbers.)
The current 'favorite' for this system has to be magnetic levitation. Passive levitation, that is, meaning that the timing and power circuitry has to be on the train, with fairly hard limits on dissipation of waste heat. I could mention quench in this context, but I'm sure you've already looked at those implications. Now what happens if you have even a momentary power or control failure during, well, most of the transit time? This is not like an aircraft failure, where there is time to react and plenty of space for recovery.
Gas bearings a la Arnold Miller's train might work, but they would destroy the vacuum and would still not prevent unique sorts of problem if their performance were to degrade...
And as you point our, Isembard Kingdom Brunel had it all down pat ...
About as much as Caselli had it all down pat with the Pantelegraph. A cautionary tale. What was it Firelock76 said about the French? C'est la vie...
... and we need only to follow his plans but replace the leather seals with rubber ones ...
... in order to move relatively small mass at blinding speeds up to 75mph, with a motive-power plant twice the size of a locomotive...
... or a kind that will not attract mice. (Actually a field mouse did eat his way through a rubber seal at the bottom of my garage door. I think this gives me special experience to be on the design team).
Mouse has even more distinctive competence to be on the design team, or at least the test team...
Problem I keep having is "sure thing for WHO"? As in 'where are the clients' yachts' but on a truly Obamanansi-esque scale. I applaud your temerity. But, since even a small investment should make me rich, I'll contribute a small investment and watch for it to grow, much like Angus Sinclair's washerwoman. More important still will be the knowledge that I have contributed in some small measure to the experience and wisdom of humanity... although, granted, in ways not directly positive...
carnej1 Paul Milenkovic carnej1 NASA, the US DOT and other entities have done R&D but nobody has a secret plan to roll out a vactrain network in the next 2 years.. Um, China in the next 10 years? Is that a prediction or can you cite an actual,funded program?
I had suggested that Vactrains would be a possibility for some advanced civilization in the future -- kinda like Arthur C Clarke's early short story "Rescue Party" that features an interstellar rescue party to an abandoned planet with the sun about to go "nova."
Somebody posted back to tell me I had it all wrong and that China plans to have a prototype Vactrain going in 10 years. So, what do I know, China is going to have their Vactrain.
Paul Milenkovic Somebody posted back to tell me I had it all wrong and that China plans to have a prototype Vactrain going in 10 years. So, what do I know, China is going to have their Vactrain.
Can you please provide the cites you were given on this project? I'd like to see exactly what its scope is, and how they plan to construct and power it...
OvermodI applaud your temerity.
Temerity is my middle name. Does this mean I won't be seeing your check in my mail?
Check in the mail? I thought I was sending it by vacuum tube when the 'pilot' bore is put in...
Overmod Paul Milenkovic Somebody posted back to tell me I had it all wrong and that China plans to have a prototype Vactrain going in 10 years. So, what do I know, China is going to have their Vactrain. Can you please provide the cites you were given on this project? I'd like to see exactly what its scope is, and how they plan to construct and power it...
Watchyapickinonme for? Forum member ontheBNSF told me China would have a Vactrain in 10 years. See
ontheBNSF Paul Milenkovic Dad's explanation is that an elliptical orbit cutting through the Earth takes 80 minutes for a round trip (OK, so a more precise number is 84 minutes then), so the one-way trip time would be 42 minutes then. But don't forget the 4 hours for clearing security on departure, immigration and customs on arrival, local ground transportation on each end, making the trip 4 hours and 42 minutes. But maybe 84 minutes is the correct time if you are doing a practical ultra-high-speed vacuum-tunnel train rather than a straight-line free-fall route. But you still need to add 4 hours to that figure. It is premature to talk about Vactrains when we can't get around to doing the first U.S. HSR, and I am not saying that the idea is practical with current technology, but the idea is serious and not an April Fool's joke -- http://en.wikipedia.org/wiki/Vactrain. For all of the ridicule directed at Vactrains, many in the broader non train enthusiast public reserve the same feelings for proper HSR. As I said, Vactrains may be a particularly energy saving mode of transportation for an advanced technological civilization in some distant future. Why is it premature or for some distant civilization in the future? China will have the technology ready in 2015.
Paul Milenkovic Dad's explanation is that an elliptical orbit cutting through the Earth takes 80 minutes for a round trip (OK, so a more precise number is 84 minutes then), so the one-way trip time would be 42 minutes then. But don't forget the 4 hours for clearing security on departure, immigration and customs on arrival, local ground transportation on each end, making the trip 4 hours and 42 minutes. But maybe 84 minutes is the correct time if you are doing a practical ultra-high-speed vacuum-tunnel train rather than a straight-line free-fall route. But you still need to add 4 hours to that figure. It is premature to talk about Vactrains when we can't get around to doing the first U.S. HSR, and I am not saying that the idea is practical with current technology, but the idea is serious and not an April Fool's joke -- http://en.wikipedia.org/wiki/Vactrain. For all of the ridicule directed at Vactrains, many in the broader non train enthusiast public reserve the same feelings for proper HSR. As I said, Vactrains may be a particularly energy saving mode of transportation for an advanced technological civilization in some distant future.
It is premature to talk about Vactrains when we can't get around to doing the first U.S. HSR, and I am not saying that the idea is practical with current technology, but the idea is serious and not an April Fool's joke -- http://en.wikipedia.org/wiki/Vactrain. For all of the ridicule directed at Vactrains, many in the broader non train enthusiast public reserve the same feelings for proper HSR. As I said, Vactrains may be a particularly energy saving mode of transportation for an advanced technological civilization in some distant future.
Why is it premature or for some distant civilization in the future? China will have the technology ready in 2015.
Citations? Check out the video posted as the grandparent post to this thread, especially the video from PopSci. Dontchaknow that if Popular Science says something is going to happen, you can expect it by next year?
Also, for you folks ragging on me about pie-in-the-sky-ballistic-intercontinental Vactrains, that was all meant as the setup for a joke punchline.
Semiballistic max time is about 54 minutes. You 'physicists' seem to be forgetting your great-circle navigation; the furthest-removed destination being only one-half a great circle (otherwise you'd just go the other way) and the effective flightpath being only slightly longer. Intercontinental tube trains are an expensive, geologically-unsound answer to a question nobody has asked. I would recommend that discussion stick to established 'destination pairs' for which the traffic is cost-effective relative to the expenses. Any thought of orbital speed -- and I haven't seen anyone indicate just what they think the speed for an 84-minute orbit actually is, although it is well-established -- in a tube on the ground goes beyond fantasy into the realm of active danger and ethical stupidity. In my opinion. For what it's worth. RME
The minimum travel time between any two points on the Earth is 4 hours and 40 minutes. That is 40 minutes for the ballistic-free-fall Vactrain and 2 hours for ground transportation and pre and postboarding screening at the two ends, get it? The joke is that if we ever get a near-instantaneous form of transportation, you will still have to tack 4 hours on the door-to-door time. Sheesh!
And the ultimate question about Vactrains is will we be able to see Mariette Hartley with two navels?
The long-distance gravity vactrains are different from the Subshuttles, which were more like a subterranean Interstate Highway System (nominally built for defense purposes, and only involving 'hundreds of miles per hour' speed.) All the stuff about air pressure and evacuation power would apply to Subshuttles, if they were real instead of 'special effects.'
Yes, I did like those double navels...
Overmod The long-distance gravity vactrains are different from the Subshuttles, which were more like a subterranean Interstate Highway System (nominally built for defense purposes, and only involving 'hundreds of miles per hour' speed.) All the stuff about air pressure and evacuation power would apply to Subshuttles, if they were real instead of 'special effects.' Yes, I did like those double navels...
I would never troll forums or engage in other obnoxious on-line activities like creating "sock puppet" accounts to facilitate the same, but I did get a chuckle at the thought setting up an account for the sole purpose serving as a "prophet" for tube trains..
my user name would be "Dylan Hunt" , of course..
Yes. And be constantly calling secretaries in Government bureaucratic offices to have them page your brother, Mike...
Overmod Yes. And be constantly calling secretaries in Government bureaucratic offices to have them page your brother, Mike...
BABOOM, no I wasn't going there I was just referencing one of Gene Rodenberry's favorite character names..
This proves that high speed trains are a socialist consprisy that will kill rock and roll and makes us listen to Disco and Europop-Just look at her red dress
https://www.youtube.com/watch?v=E7M3EOD_GzE
Bonas This proves that high speed trains are a socialist consprisy that will kill rock and roll and makes us listen to Disco and Europop-Just look at her red dress https://www.youtube.com/watch?v=E7M3EOD_GzE
I don't see how this would be "socialism". Glenn Beck and his minions have perverted that word beyond its meaning. Socialism is workers owning the means of production so unless this swissmetro will be worker owned or worker runned I don't see the "socialism"
Railroad to Freedom
BonasThis proves that high speed trains are a socialist consprisy that will kill rock and roll and makes us listen to Disco and Europop-Just look at her red dress
I refuse to listen to those high fallutin Eurapeen klassikal musicalsisian guys play anythin. I want Elvis.
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