Democratic Underground Latest Greatest Lobby Journals Search Options Help Login
Google

Are there any high speed commuter trains that run in vacuum tunnels?

Printer-friendly format Printer-friendly format
Printer-friendly format Email this thread to a friend
Printer-friendly format Bookmark this thread
Home » Discuss » Topic Forums » Environment/Energy Donate to DU
 
Boojatta Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 08:42 AM
Original message
Are there any high speed commuter trains that run in vacuum tunnels?
I mean tunnels that contain no air. Of course, the trains would need the kinds of systems that airplanes have to handle to ensure that passengers have breathable air all the time, even in an emergency.
Refresh | 0 Recommendations Printer Friendly | Permalink | Reply | Top
Fumesucker Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 08:46 AM
Response to Original message
1. The restaurant in the train station would suck..
No atmosphere..
Printer Friendly | Permalink | Reply | Top
 
formercia Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 09:17 AM
Response to Reply #1
7. +10
That train went right past them....
Printer Friendly | Permalink | Reply | Top
 
Yo_Mama Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 10:00 AM
Response to Reply #1
16. Thank you
I needed my daily dose of laughter medicine - that's pretty darned good!
Printer Friendly | Permalink | Reply | Top
 
Turbineguy Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 08:46 AM
Response to Original message
2. Interesting idea.
If the cost of lowering the air pressure could be justified against the amount of energy expended by the train to push the air.
Printer Friendly | Permalink | Reply | Top
 
FBaggins Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 08:58 AM
Response to Original message
3. Nope... but it's been the subject of speculation for many decades.
Combine the vacuum with a maglev system and you could make transatlantic crossings in an hour or less... and expend remarkably little energy in the process.

But the capital costs would be a nightmare.
Printer Friendly | Permalink | Reply | Top
 
elleng Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 09:03 AM
Response to Reply #3
4. Sounds like a nightmare to me, and I ain't no chicken!
Printer Friendly | Permalink | Reply | Top
 
Boojatta Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 09:09 AM
Response to Reply #3
5. How much is spent every year on illegal drugs?
Edited on Tue Sep-20-11 09:10 AM by Boojatta
What if they were legalized, with a markup of 25% to help finance the tunnels?
Printer Friendly | Permalink | Reply | Top
 
FBaggins Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 09:24 AM
Response to Reply #5
9. Lol... not nearly enough.
This would be orders of magnitude larger than that.

Take, for example, the Chunnel. It's about 30 miles long and comparatively "shallow" - yet cost about 15-20 billion 2011 dollars (call it half a billion dollars per mile).

A transatlantic tunnel would be more than 100 times as long. Would be a maglev. Would need to maintain a vacuum. Would be under much deeper water (and likely deeper into bedrock)... and would have to cross the mid-atlantic ridge (a major tectonic plate boundary).

It's an engineering challenge many MANY times greater than the Chunnel. Certainly costing in the many trillions of dollars.

Smoking something illicit might make you want to ride it... but couldn't pay for it. :)
Printer Friendly | Permalink | Reply | Top
 
AtheistCrusader Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 10:13 AM
Response to Reply #9
17. And as expensive as the Chunnel was, I bet it isn't water-tight.
I bet it's got some gnarly sump pumps running all the time.
Printer Friendly | Permalink | Reply | Top
 
FBaggins Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 11:39 AM
Response to Reply #17
23. I'd imagine so
Edited on Tue Sep-20-11 11:45 AM by FBaggins
and pumping water over 15 miles is likely easier than 1,500.

Nor is the Chunnel "sucking" like an evacuated tunnel would.

And just think of the construction process! Chunnel workers could go home at night since the farthest "in" they could get is about fifteen miles. When the TBM get's 1,000 miles from shore you have to have hundreds of guys living out there.
Printer Friendly | Permalink | Reply | Top
 
txlibdem Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 06:15 PM
Response to Reply #9
32. The Channel Tunnel cost less than 1/6th of what the US Interstate Highways did.
http://en.wikipedia.org/wiki/List_of_world%27s_most_expensive_transport_infrastructure ($114 Billion, Chunnel ~15 Billion)

"The network has since been extended and as of 2006 it had a total length of 46,876 miles (75,440 km).<1> About one-third of all miles driven in the country use the Interstate system (2003 figures).<2>"
... from http://en.wikipedia.org/wiki/Interstate_Highway_System

Granted, tunneling under the seabed would be possible for only part of the journey; http://en.wikipedia.org/wiki/Seabed

I propose a structure that naturally reaches a neutral buoyancy, becoming at equilibrium around 200 meters below the surface of the ocean, that's only 600 ft and wouldn't stretch our abilities to use mini-subs and ship-board cranes to position the tunnel section currently under construction. That depth will allow construction to be completed in sections by ships on the surface while not interfering with surface vessels (I'd need to research the draft of a fully laden oil tanker and the US Navy aircraft carriers but I think I'm right). It would also not be impacted by storms on the surface of the sea.

In order to remain buoyant it would have to have an airtight outer layer with the correct amount of air to provide the buoyancy. Since seawater can vary in its density there may need to be a system of air compressors to change the air to a highly compressed gas, thus reducing buoyancy and the opposite is true in other areas. Some sort of active measuring and computer controlled response system would be needed. IIRC a submarine uses a system such as this to maintain a certain depth, making sure the tendency to rise to the surface is in equilibrium with the force that would tend to make a multi-ton metal structure sink, thus it maintains a certain depth without expending fuel. http://en.wikipedia.org/wiki/Buoyancy#Compressible_fluids_and_objects

Inside the sections would be the evacuated tubes through which the train would move in a vacuum, propelled by Magnetic Levitation.

I have no idea at this point how much such a submerged high speed rail line would cost.
Printer Friendly | Permalink | Reply | Top
 
Yo_Mama Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 10:00 AM
Response to Reply #3
15. Also extremely expensive construction
A tiny leak in tunnel at negative pressure would be interesting!

Printer Friendly | Permalink | Reply | Top
 
liberal N proud Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 09:11 AM
Response to Original message
6. Like Mail tubes
I am thinking that would take one hell of a vacuum pump to pull enough pressure to move a train full of people.

It would be interesting ride though.

Printer Friendly | Permalink | Reply | Top
 
formercia Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 09:20 AM
Response to Reply #6
8. Think of it like thrust, but in the negative sense.
Take the area of the Tunnel face and calculate the amount of vacuum required to give a given amount of negative thrust.
Printer Friendly | Permalink | Reply | Top
 
FBaggins Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 09:27 AM
Response to Reply #8
11. The vacuum wouldn't serve to provide motion to the train.
Edited on Tue Sep-20-11 09:27 AM by FBaggins
It would be to eliminate air resistance.

Making it a maglev would reduce resistance from friction.

So once you accelerated the train, the cost of travel would be remarkably low. If you recapture that energy on the receiving end, it gets even cheaper. Operating the giant airlocks would be a substantial portion of your energy expenditure.
Printer Friendly | Permalink | Reply | Top
 
formercia Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 09:28 AM
Response to Reply #11
12. ...but waiting on the platform would suck.
IMHO
Printer Friendly | Permalink | Reply | Top
 
FBaggins Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 09:35 AM
Response to Reply #12
14. Lol... well yes.
But there would be airlocks for the train itself... so the passenger/freight loading area would be quite similar to a "normal" train.

My guess is that you might spend more time going through a series of "locks" and then accelerating (and the reverse on the other end) than the actual travel time of the trip would take.
Printer Friendly | Permalink | Reply | Top
 
Tesha Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 11:15 AM
Response to Reply #6
19. The earliest NYC subway was built like that, but that's not what we're discussing here.
Here, we're discussing a train that runs in a fully-evacuated
tunnel (with vacuum at both ends) as a way of eliminating
the friction from air drag.

Tesha
Printer Friendly | Permalink | Reply | Top
 
formercia Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 02:11 PM
Response to Reply #19
24. Inner Space.
We make Space Capsules to put people in orbit. Technically. it could be done. Maintenance would be a nightmare unless one could isolate segments.
Printer Friendly | Permalink | Reply | Top
 
tridim Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 09:27 AM
Response to Original message
10. A good idea if it were possible.
Edited on Tue Sep-20-11 09:28 AM by tridim
It's difficult to hold a vacuum even in small scientific equipment.

It would probably cost a trillion dollars per mile of tube.
Printer Friendly | Permalink | Reply | Top
 
Tesha Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 11:18 AM
Response to Reply #10
20. You don't need a very good vacuum; the friction would drop roughly in proportion...
...to the air pressure drop.

The idea is entirely possible with modern technology, it's
just not yet practical.

Tesha
Printer Friendly | Permalink | Reply | Top
 
PoliticAverse Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 09:33 AM
Response to Original message
13. Gravity Vacuum Transit...
Printer Friendly | Permalink | Reply | Top
 
Tesha Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 11:19 AM
Response to Reply #13
21. "Connecting to all points in (IIRC) 45 minutes!" (NT)
Printer Friendly | Permalink | Reply | Top
 
muriel_volestrangler Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 10:31 AM
Response to Original message
18. I doubt commuter trains would ever use a vacuum
As people point out, you need an airlock before and after each station, which needs to be big enough to hold the train during the time that air is introduced/removed and it's accelerating/decelerating. That's a significant operation, and not worth it, I think, for a train expected to stop every few miles. All that to save a minute or two between stops wouldn't be done, I think. Only worth it, even in theory, for long distance travel.
Printer Friendly | Permalink | Reply | Top
 
Tesha Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 11:21 AM
Response to Reply #18
22. Equip the car doors with docking collars; no airlock required. (NT)
Printer Friendly | Permalink | Reply | Top
 
muriel_volestrangler Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 05:43 PM
Response to Reply #22
30. Yeah, I guess that would solve that
I'm not convinced that commuting will need a technologically complicated solution like this, nevertheless.
Printer Friendly | Permalink | Reply | Top
 
formercia Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 02:14 PM
Response to Reply #18
25. Just imagine how much energy it would save
if High Speed Rail would operate in a Tunnel at, say, .25 atmospheres.
Printer Friendly | Permalink | Reply | Top
 
muriel_volestrangler Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 05:37 PM
Response to Reply #25
29. Perhaps; but that's high speed, not commuter rail (nt)
Printer Friendly | Permalink | Reply | Top
 
formercia Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 02:20 PM
Response to Reply #18
26. Perhaps something like an Airliner at cruising Altitude.
Edited on Tue Sep-20-11 02:21 PM by formercia
Printer Friendly | Permalink | Reply | Top
 
txlibdem Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 04:25 PM
Response to Reply #18
28. If economics are the ruling factor then you are right
But if passenger comfort and convenience, i.e., minimizing the total time per trip were the prime consideration then whether it's "worth it" to save a few minutes might be a different answer.

We all seem to have conditioned our brains to think in terms of dollars and cents. I can pretty much guarantee you that that is a temporary system. Capitalism has about 20 years left, then it'll be gone in a flash historically speaking.
Printer Friendly | Permalink | Reply | Top
 
hunter Donating Member (1000+ posts) Send PM | Profile | Ignore Tue Sep-20-11 03:55 PM
Response to Original message
27. Just make a universal speed limit of 50 kph.
Then air resistance doesn't matter so much.

Go ahead, kick back, order a beer, open a good book, and enjoy a week long ride on the slow train or ocean liner.

Everybody is in such a useless hurry these days. There's no good reason to go fast except for emergency services -- ambulance, paramedics, fire, police, etc.
Printer Friendly | Permalink | Reply | Top
 
ironrooster Donating Member (273 posts) Send PM | Profile | Ignore Tue Sep-20-11 05:47 PM
Response to Original message
31. Brunel tried it - in the 1840's (partial vac)
Printer Friendly | Permalink | Reply | Top
 
DU AdBot (1000+ posts) Click to send private message to this author Click to view 
this author's profile Click to add 
this author to your buddy list Click to add 
this author to your Ignore list Fri May 09th 2025, 04:01 PM
Response to Original message
Advertisements [?]
 Top

Home » Discuss » Topic Forums » Environment/Energy Donate to DU

Powered by DCForum+ Version 1.1 Copyright 1997-2002 DCScripts.com
Software has been extensively modified by the DU administrators


Important Notices: By participating on this discussion board, visitors agree to abide by the rules outlined on our Rules page. Messages posted on the Democratic Underground Discussion Forums are the opinions of the individuals who post them, and do not necessarily represent the opinions of Democratic Underground, LLC.

Home  |  Discussion Forums  |  Journals |  Store  |  Donate

About DU  |  Contact Us  |  Privacy Policy

Got a message for Democratic Underground? Click here to send us a message.

© 2001 - 2011 Democratic Underground, LLC