Hey, if you could make the tunnel rigid enough and the train fast enough, it could effectively go into an underwater orbit during the crossing. Very speculative, but cool.
Well `anywhere to anywhere’ as long as your anywheres are at antipodes, anyway. (You do have to go through the center of the Earth in a straight line and not a parabola for that time to be correct, right?)
Which makes it pretty much useless.
No, you’ve missed the point entirely. It works for a tunnel connecting any two points on the earth’s surface.
I haven’t done the math, but as I heard it, the time was the same from anywhere to anywhere. If you dug a straight-line tunnel from New York City to London, it would cut through the Earth the way a chord line cuts through a circle. It would start out downhill at some angle, level off halfway, and momentum would carry it uphill to the end (all in a perfectly straight line, think about it). Barring trivialities like friction, you’d just have time to grab on to something before you started rolling backward into the tunnel again. The claim is that the downhill acceleration and the length of the tunnel cancel each other out, and the travel time is the same for any two points on the globe.
Heh. That makes sense. The difference in the lengths of the paths are offset exactly by the difference in steepness (and, therefore, acceleration).
Neat. Thanks. 
45 posts and no one has mentioned how hard it is to find passengers for the Concorde?
How in hell are they ever gonna find a thousand people who are in that much of a rush to cross the Atlantic on a regular basis?
Not to mention if you went “straight up” and “straight down” this would mean in relation to the earth’s surface, and in reality you’d be carrying the horizontal component of the earth’s roation with your velocity. Relative to the earth, you’d come down at or near the spot you started (give or take wind speed and jet stream). You’d need to launch at an angle anyways, not that this would be a practical form of traval anyways.
Well, according to Donald Fagan it will take 90 minutes from New York to Paris, under sea by rail.
Yeah, but at something $2K+ for a ticket, it’s pretty easy to see why they’re having problems. Now, if they could get the ticket price down to something like $1K or less, they’d see a lot more business. (Get the tunnel ticket prices down to around $50 and you’ll have no end of people wanting to take a ride! Just think of that! Hordes of ugly Americans running all over Europe! :eek: It’ll be like WWII again, only without the shooting! )
Naturally it will have to be demolished in the name of progress.
Chekmate: Pneumatic and atmospheric railways have been around for over a hundred years. (Well, I say “been around”, but I’m not sure any still exist). They worked, but not terribly well for a variety of reasons.
As for stopping the air from getting out of a vacuumed tunnel, see my previous post.
Also I think there never will be an underwater, transatlantic tunnel, by the time we have the tech to make, it it will be much safer and cheaper to take a sub orbital flight.
Of course, shortly after this will be announced a new high speed plane which will be able to complete the trip in seconds, thus making the tunnel obsolete!