Vacuum Freight Tubes   (+4, -3)  [vote for, against]
Send goods between major shipping hubs by vacuum tubes

We all know those delightful little tubes at banks that send canisters back and forth with money and documents. Why not implement this on a national scale?

Between Chicago and New York, LA, etc., have Vacuum tubes capable of holding 3 meter or so diameter canisters. Post offices just fill them up at terminals until they're full (many times a day), and send them off. Each canister would fit tightly enough that the vacuum would persist behind it as well. So despite taking more power, many canisters could move at once.

I feel like this would be way cheaper to operate (if not build...) than train and truck and airplane transportation, since it can be very low friction, you can use any energy source you want, since it would only be applied at terminals and booster stations every 100 miles or so (nuclear doesnt quite work onboard an 18 wheeler, despite being much more efficient than diesel).

Fewer accidents on the roads, more reliable delivery dates, less road construction work (special canisters would wear the tubes down much less than trucks do for roads), sheer awesomeness, etc.
-- Smurfsahoy, Mar 16 2007

Delivery of goods (and people) by vacuum power http://en.wikipedia...Atmospheric_railway
[AbsintheWithoutLeave, Mar 16 2007]

Maglev train in vacuum tubes [placid_turmoil, Mar 16 2007]

Not so much freight as fright Pneumanic_20transport
[Ling, Mar 16 2007]

Ever hear of gravity? Your capsule is going to be scraping along the bottom of the tube the whole time.

Those tubes at the bank? They work by differential pressure. A machine is either sucking air out from in front of the capsule or pumping it in behind.
-- Galbinus_Caeli, Mar 16 2007

Yes, I know. This has a pump pushing or pulling it too, every 100 or 200 miles or whatever. But they can all be run on mains electricity.

As for gravity - yes, it will "scrape," but less so than a truck does. This capsule can be fitted with bearings that create much less friction, and the uniform size and distributed contact in the tube means that it wont wear down as quickly, so it can be cost effective to line it with teflon or something to make things even better. The idea is just to make it smoother than a train or truck, thus savings. Eliminating gravity entirely is not necessary.
-- Smurfsahoy, Mar 16 2007

So you have a pumping station every hundred miles? That means you can only have one capsule per hundred miles. Also you are going to have to pressurize (or depressurize) 100 miles of tubing to move one capsule that distance.

Doesn't sound terribly efficient to me.

Bearings on the bottom of the capsules? Yeah, that makes sense. Maybe you should also include some sort of internal power source to move the capsules along the tube so you don't have to keep pumping air in and out of the entire tube.
-- Galbinus_Caeli, Mar 16 2007

[bigsleep] - that link only describes a vacuum-powered railway, not a tube system
-- coprocephalous, Mar 16 2007

At first I thought this was going to be Vacuum on both ends and like a magnetically indused train for higher efficiency. No air resistance would be almost worth the bother if you were moving enough material.

Like the Swiss Metro link shows.
-- MercuryNotMars, Mar 18 2007

random, halfbakery