So you know those casters embedded in the ground and in loading vehicles at airports, that help move containers from say, a loading vehicle into the airplane's belly?
Imagine 3,000 miles of those casters, underground, shuttling shipping containers from one end of the US to the next (New York City to SF). Two lanes, one for east to west, the other going west to east, connecting the coasts' ports. Further lanes going from the midwest (St. Louis, Missouri?) to northern (Chicago?) and southern ports (Jacksonville, FL and/or New Orleans?), with regional hubs along the line.
Why? Efficiency, Ecology, Economy. The whole thing, apart from manning the stations for loading/unloading the containers, could be fully automated.
And before you say "having rolling casters running full tilt 24/7, across the continental US, is gonna be hella expensive, electricity-wise!", I say: The casters don't have to be rolling non-stop, and could incorporate some kind of fly-wheel energy-saving tech to avoid huge power bills :)-- slater, Nov 09 2011 might share tunnels and bridges with this corridor Real_20Corridor_20across_20the_20States [swimswim, Nov 10 2011] Old variant on this Idea http://en.wikipedia...The_Roads_Must_RollSuppose long-distance roads were basically conveyor belts.... [Vernon, Nov 11 2011] This exemplifies most math and engineering tutorials. http://www.funz.eu/...-To-Draw-An-Owl.jpg [Voice, Nov 18 2011] Too late! I'd already said "having rolling casters running full tilt 24/7, across the continental US, is gonna be hella expensive, electricity-wise!" before I hit the last paragraph.
Some time ago (around the 1750's, I believe), we started developing something called the "canal". I'll have a Google and see if it ever took off.
But, how rude of me! Welcome to the HB.
Ah, hang on. Welcome to posting on the HB.-- MaxwellBuchanan, Nov 09 2011 If you put the castors on the bottom of the containers, you could make them run on smooth strips of metal with low friction. Best make them quite big castors, then you only have small points of contact capable of supporting a lot of load.
Maybe you could link the containers together, with a single mobile power unit at the front ? That would reduce maintainance requirements.
Perhaps you could find a catchy name for it, like maybe "train" ?-- 8th of 7, Nov 09 2011 //Maybe you could link the containers together, with a single mobile power unit at the front//
Yes,but it wouldn't have the same majesty on film...imagines the HD footage shot from helicopter...David Attenborough voice-over "...and here we see the last of the migrating shipping containers heading towards the west...and a pack of coyotes with can openers are circling the one with all the dog food in it.."-- not_morrison_rm, Nov 09 2011 O hai y'all.
I see the snark runs deep, here. :P-- slater, Nov 10 2011 As my friend(s) and colleague(s) the Borg have pointed out, this is utterly baked in railroad form. It's called intermodal shipping, and would help with many of our current economic and environmental issues if the fucking teamsters lobby would kindly step the hell out of the way.-- Alterother, Nov 10 2011 Compared with rail, casters would require the same grading. At the same time they'd be using less metal overall in construction; picture a mass-produced caster unit staggered every 10 feet, instead of 2x10 foot lengths of rail.-- FlyingToaster, Nov 10 2011 Slater, ignore 21 IQ. That he equates quantity of HB posts with job success shows you how much that comment is worth. Nice weather in DC today, isn't it?-- swimswim, Nov 10 2011 // the snark runs deep //
Not necessarily - it might be a Boojum ...-- 8th of 7, Nov 10 2011 Hmm.... let's look at installation
Mile-by-mile: caster - rough grading, say to 4 feet. - sinking 528 cement pylons 8 ft down - capping each pylon with an aluminium/steel caster.
Mile-by-mile: rail - fine grading, filling with gravel 8-10 feet wide - railway ties: 2,640 of them - 2 miles of rail, welded
Caster system is cheaper and less intrusive to the environment. [+]-- FlyingToaster, Nov 11 2011 Somehow I doubt that. With casters you have only the momentum of the containers, which is continuously sapped by caster wheels which need to be spun up to speed, ie. energy drain.-- RayfordSteele, Nov 11 2011 Alterother: With my idea (and almost end-to-end automation), you don't have to deal with evil teamsters any more!
Flyingtoaster: So you're for my genius idea? Not quite sure what the 528 cement pylons are for, tho :(
21 Quest: Quality over quantity, of course.
RayfordSteele: Maybe this needs casters with built-in flywheels or something?-- slater, Nov 11 2011 //528// 5,280 feet/mile, 40 foot container which must be balanced on (at least) 3 points at any given time = a caster every 10 feet (one on the left side then, 10 feet further on, one on the right side, etc.).
//energy drain// The figure to beat is the rolling resistance of a normal pair of train trucks(the wheels assembly).-- FlyingToaster, Nov 11 2011 Hmm... thousands of pounds rolling on 8 huge metal wheels vs. inertia of millions of stopped smaller wheels with bearing losses. Could be an interesting comparison.-- RayfordSteele, Nov 11 2011 // The figure to beat is the rolling resistance of a normal pair of train trucks(the wheels assembly). //
Which is incredibly low. An entire 1,200 -1,600 lb. assembly on level track can be moved with the slightest nudge, and easily rolled along by hand. The issue I see here (aside from the teamsters, who, despite what you may think, will fight (and usually defeat) anything that poses a threat to long-haul trucking) is that smaller wheels = more wheels = more friction and more parts that need replacing. I know I've pointed this out before, but freight cars are built out of big beefy chunks of steel because they must withstand tremendous wear and tear, elemental extremes, incidental damage, etc.-- Alterother, Nov 11 2011 These things are called shipping containers because when you want to go from one coast to another, you put them on a ship.-- ldischler, Nov 11 2011 Well yes, when the coasts are on two different continents.-- swimswim, Nov 11 2011 [bigs], look out of your window.
You see that crouwd of people with flaming torches and scythes and pitchforks ? And the noose ?
They've come for YOU. And you have only yourself to blame. You knew what you were saying, you knew it was very very bad and wrong, and now you're going to pay the price.
Oooh, look, a Wicker Man ... excellent.-- 8th of 7, Nov 12 2011 "Perhaps if we built a Giant Wooden Badger ... "-- 8th of 7, Nov 12 2011 Can anyone smell elderberries ... ?-- 8th of 7, Nov 12 2011 Building on what everyone said, I'm looking at this with symmetry in mind. Surely everything will have to be as big/robust/frictionless etc. as the components of existing trains - I mean, it would be ludicrous to put little airport-style casters on the bottom of train carriages and locomotives, and run the trains on the bottoms of upturned shipping containers, so the inverse of that would also be ludicrous - except for short distances at low speeds.
So I imagine something more like inverted railway bogeys emplaced at intervals of about 20 feet (either opposite each other, or staggered a la [FlyingToaster]) on the ground, and each shipping container mounted on a sled-like chassis incorporating a length of upside-down rail on either side.
This "upside-down railway" version may be conservative, but it's modelled on the only system (short of radical departures such as canals and mag-lev) that has been proven to be effective and efficient.-- spidermother, Nov 12 2011 The advantage of having the running gear on the cars is that they can be brought to a shop for m&r, whereas a 'track' made of inverted bogies would require field repair. Also, with intermodal cars, the containers can be stacked double, meaning twice the shipping volume per length of train.-- Alterother, Nov 12 2011 Bun for upside down trains-- Voice, Nov 12 2011 No, and to quote a great hero of mine, I can imagine a lot.-- Alterother, Nov 13 2011 I don't think I have ever noticed built in casters at airports. Googling did not help me. Big tubs of luggage have casters on the bottom. If someone can link a picture of the in-ground ones I would like to see it.-- bungston, Nov 17 2011 Luggage casters would be absurd unless you were shipping luggage... in which case they're still not that good. I think we've defined 'casters' topically as wheels set in the ground.-- FlyingToaster, Nov 17 2011 When I think caster I think of a caster wheel on the bottom of a cart or dolly that might be pushed in any direction. A caster wheel has a vertical stem that allows the axis of rotation to turn 360 degrees. Do the ones set in the ground still do that?
hmm. maybe that is my problem with finding these online - I used caster as a term. I bet the airport ones do not rotate their axis because if fixed in a track that would be counterproductive. Those are not caster wheels, but have some other name.-- bungston, Nov 17 2011 "conveyor belt" ?-- FlyingToaster, Nov 17 2011 Look up "skate wheel conveyor". That's pretty much what this is on a large scale.-- MechE, Nov 17 2011 Because I didn't feel like selecting one of the thousands of sources for the same thing.-- MechE, Nov 17 2011 Suppose instead you elevate the casters with hot air balloons... I bet this would cost less than tunnels and would get the same results.
Bonus: you can have elevators and places for the containers to roll downhill. This will let you provide energy at fewer places.-- Voice, Nov 17 2011 Hot-air balloons aren't dangerous enough. Better use hydrogen.-- Alterother, Nov 18 2011 Given the average friction of the rail I wonder how high you would have to go for a relatively steady pace for 3,000 miles
EDIT: I'm stuck at 1.3wn + 29n because I have no idea what those numbers represent. Also I hate it when they break out greek letters without explaining them in a tutorial. It's like that 2 step "how to draw an owl"-- Voice, Nov 18 2011 Show your work and we can answer, I'd guess weight and normal force for w and n respectively, but you shouldn't have both in an equation once you've gotten that far along.-- MechE, Nov 18 2011 Rockets, for gods' sake!-- pocmloc, Nov 18 2011 This one's easy, [voice].
Minimum height = rolling resistance coefficient * horizontal distance = 0.0002*3000 to 0.001*3000 = 0.6 to 30 miles
Rolling resistance coefficients from Wikipedia, "Railroad steel wheel on steel rail".
Extra height will be needed for air resistance, but that depends heavily on speed and aerodynamics.-- spidermother, Nov 18 2011 // average friction of the rail //
Rail friction is relatively unimportant; what matters is the friction of the bearing.
If the frictional coefficient is 1 then energy loss depends solely on bearing losses in the axle.
If it's zero, you might as well use a skid. But that means "wet ice on wet ice" which has as near zero a slip coefficent as is practicably achievable.-- 8th of 7, Nov 18 2011 What matters is rolling resistance. Surely wheel-track interaction contributes, not just bearing resistance. Obviously, the importance of each depends on the condition of the track, wheel, and bearing, and the number of cats on the track.-- spidermother, Nov 18 2011 re rail vs bearing: if the substrate is frictionless then you will not roll forward. But if the part of the wheel does not move relative to the substrate (which for a wheel would be skidding) are there frictional losses? 8th maybe that is why you say rail friction is unimportant.
How does maglev work? Captive magnets instead of captive rollers? I like the nonmoving parts aspects of that. But probably you would have to make the carts long to spread the weight over many magnets.-- bungston, Nov 19 2011 random, halfbakery