WOW!!

Truly, i think they should put certain projects up for a.. well.. vote.. and if people want to fund it.. they can.. which would help it be done a lot faster. I myself would give to help fund something like that. With enough money, i'm sure they can build it faster.

that would be awesome though.... but wait.. i live in California.. and i'm still waiting for that purposed bullet train from the north to the south. I could really use that about now. I love driving my prius.. but if it took only 2 hours to get to L.A.... and i could see the person who i care for greatly whenever i want... i would be very happy.

Plus.. it's a bullet train... i would still feel pretty green :mrgreen:

 

reading that post again.. i think they should just have a world train... a huge train that would wrap around the world. stop in a few key places on each continent. that, would be awesome. We don't want any accidents though.. so the whole thing would be incased.. be bomb proof.. and .. well.. plane proof.. just incase.

 

It is going to float 85' below the surface, maintaining an absolute dead straight point to point tunnel for 3,000 miles anchored to nothing holding it in place? And they are going to maintain this vacuum how? Then of course there is the matter of acceleration/deceleration - 5K MPH? OK, maybe my great great great grand kids will see it but I expect Star Trek type transporters will show up first.

 

Anyone got the math to calculate how many G's would be placed upon the passengers by a train that accelerated and decelerated rapidly enough to make the NY - London trip in 54 minutes?

And who's going to invest 15 trillion bucks in a project that won't come on line for 100 years? Plus, the operating cost is going to put the price of tickets through the roof! Remember Concord? Great idea: London to NY in 4 hours. But it was too expensive to operate.

 

ok.. we'll start off simple.. a huge sling-shot... and a capsule you sit in.. with some parachutes... it might work... worlds largest sling-shot

 

Hmm, what about the effect of vibration and magnetic fields on Marine Life?

 

Here comes the physics...

Given:
total distance: 3100 miles
total time: 54 minutes

The smallest possible acceleration is achieved by accelerating constantly until the midpoint and then decelerating constantly until the destination. So we split the problem in half to see how much acceleration each leg would involve:

distance (d) = 1550 miles
time (t) = 27 minutes

Given:
[font=Courier New:1065cb36f4]a = 2d / t^2[/font:1065cb36f4]

Solve for a:
[font=Courier New:1065cb36f4]a = 2(1550 miles) / (27 minutes)^2[/font:1065cb36f4]

... which Our Lord the Almighty Google tells us equals about 6.2 feet per second per second, or less than 1/5 the acceleration due to gravity.

No sweat. Even the space shuttle only pulls 3 Gs during takeoff -- you'd hardly even notice 1/5 G. If you wanted to give passengers some time in the middle to get up and stretch, you could accelerate a little harder and coast for a while at the midpoint.

That's probably where they got their 5,000 mph top speed. Using my acceleration your velocity at the midpoint would actually be:
[font=Courier New:1065cb36f4]
v = a * t = (6.2 feet per second per second) * (27 minutes) = about 6,800 mph[/font:1065cb36f4]

 

Blast! You beat me to it! :mrgreen:

 

Ah, they used 6.8 feet per second per second acceleration so the numbers would all work out nicely:
[font=Courier New:0eac633cfb]
a = v / t
a = 5000 mph / 18 minutes = 6.8 feet per second per second
d = 1/2 a * t^2
d = 1/2 * 6.8 f/s/s * (18 minutes)^2 = about 750 miles
5000 mph * 18 minutes = 1500 miles
[/font:0eac633cfb]
You spend the 1/3 of the trip time accelerating up to 5000 mph (traveling 750 miles), cruise at that speed for 1/3 the time (going 1500 miles), and then spin your chairs around the other way and decelerate for the last 1/3 of the trip (another 750 miles).

Yeah, that's what I meant about the coasting in my first post.

 

Okay, so acceleration isn't a problem. What about operating costs?

Or, how about these numbers: (Speculation, of course, just like the concept.)

$15 trillion to build. It takes a hundred years, so we're talking very long-term loans, so let's say 10% interest, means $1.5 trillion per year in interest payments. But since the thing produces no revenue until it's completed, money borrowed early to start it off pays compound interest. Let's be really really generous and say that by completion, they're paying $3 trillion a year in interest. Now let's say that three thousand people a day ride on this thing (population growth and intercontinental commuting). Round it off to a million passengers a year.

They'll have to charge $3 million for a one-way ticket just to pay the interest, and that does not even count the operating costs such as fuel, ticket agents, attendants, maintenance, depreciation of rolling stock, in-flight peanuts, security cops, and military submarines to prevent some gang of malcontents from bombing the tunnel.

It's only $100,000 to ride that new private sub-orbital rocket ship.

Sounds like make-believe to me.

 

Wasn't the Chunnel suppose to revolutionize cross-Channel commerce and such? And isn't the Chunnel company hemoraging money like crazy?

Extreme Engineering also had a show about a cross-Gibraltar bridge, a giant floating city, and a massive city-tower. They were all pretty cool looking ideas, but seemed completely unnecessary from a practicality standpoint.

 

$15 trillion? Let's just empty Uncle Dick Cheney's pockets, and while we're at it, Ken Lay, Halliburton, the Bush family, and the Bin Ladens. That should probably be plenty enough.

-m.

 

Even though these kinds of ideas aren't very practical (and economically sound), it's great to watch those shows.

As for the accelerations, I wouldn't mind if it was a bit faster than just 1/5G...

And for my holiday to Cornwall I travelled through the Chunnel. It's quite a ride: you hardly notice it. Takes less than 30 mins to go from end to end. I like it.

 

The only way government is going to finance a big project is by selling bonds. But the more bonds you try to sell, the higher the cost becomes, as you need to entice more people to buy.

Now, here's the kicker: nobody's going to buy a 100-year bond. So you sell 10-year bonds and renew them every ten years. But now your renewal bonds are competing with your new bonds, as the project needs continual financing, and as the total debt mounts the interest rate you have to offer skyrockets, and the effects ripple throughout the economy.

Then, in 50 years from now, with no new money available and crippling interest payments, the government finally decides to cancel the project and default on the bonds. After all, they're still 50 years from completion and nobody in power is going to live to see any benefits from the project.

Finally, there's interest to be paid right from the start, and even if you pay the interest with more borrowing, that affects the whole economy by driving interest rates up. What politician or what voter is going to agree to begin paying for a project that she or he will never see completed?

 

There's a generic way to make money, and if you do it right it's legal, as long as nobody can prove that your intention was fraudulent:

Figure out a hare-brained scheme; convince people to invest in it; set up an office and pay yourself a salary until you run out of money and the project fails. The corporation declares bankruptcy and its assets are sold to pay the investors 5 cents on the dollar. You, as an employee, get to keep the salary you've paid yourself. Since you paid yourself a very generous salary, you can retire.

I suspect that a lot of these projects fall into that category. It looks even better if (like the Concord or the chunnel) the project actually functions for a decade or two before it goes bankrupt, plus you get paid longer.

 

So, about the price of a hotdog in 2100, then. :wink:

Not that I believe the thing'll ever happen, but the programme was a fun bit of fantasy (and interesting in the parts where it touches the Real World).

Concorde was an Anglo-French joint venture, and a fairly early experiment in international engineering cooperation. Many of the lessons learnt paved the way for later projects such as the Channel Tunnel (but for a counterexample, see Eurofighter ).