h a l f b a k e r yIs it soup yet?
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Stopping and starting subway trains takes a lot of energy, it also reduces the total throughput of the system. This system keeps the trains moving at full speed and just accellerates and decellerates the passengers.
The train station is a large horizontal rotating disk. Customers enter and exit
through escalators and elevators at the center. Around them they see a circular room with doors around the edge marked with all the destinations available on that line. The passenger passes through the door into a small capsule with four seats and a small standing/ package space.
When a train approaches the station, the doors to any occupied capsule close and the capsule slides outward on the disk. The outer rim of the disk is travelling at the same speed as the train, so as the train passes, the capsule is slipped into a slot. When the destination for the capsule is reached the capsule slips out to the rotating disk of that station, and is cranked into the center where the doors open into the central room.
The passenger then walks to the elevator and rises up to the street.
Scientific American 1905
http://www.endex.co...8/SciAm19050318.htm
...the train shall not stop, and we are forced to use a slowly-rotating loading-platform... [xaviergisz, Apr 20 2006]
US patent 3,727,558
http://patft.uspto....558&RS=PN/3,727,558
transport system with continuously moving platform [xaviergisz, Jul 09 2006]
Non-Stop train
http://www.carectom...in-that-Never-Stops
[MisterQED, Jul 02 2008]
[link]
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I like this. Assume that the station is 1/4 mile radius, or 440 yards and revolving at 1 revolution/minute. Then the outside rim is moving at 2x440xpi =2764 yards/minute, or 94mph - a decent speed for an underground train. |
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We still have a lot of els (where the subway runs above ground on an elevated track) in the outer boroughs here. I have visions of one of these capsules coming unglued and flying across the Bronx rooftops. |
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This idea is already in use at the small-scale at least for loading water-based amusement park rides, and works well. |
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Centrifugal force will likely be an issue at those speeds, but you could deal with this by shaping this platform like a bowl. |
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"Odd as it may seem, we have subways
for
our convenience, not that of the
engineers."
Well, the passengers do get shorter
travel
times as the train does not have to
stop. |
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I think Worldgineer is right about the
forces and I don't think a bowl is
sufficient for hippo's example. A quick
back of eyelid calculation is telling me
that the outside of the platform would
be pulling about 5g. |
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Passengers also get to enter their capsule as soon as they enter the station, and don't have to pay any attention until the doors open at their destination. |
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[st3f] I think hippo is a bit optimistic about the speed. 30mph is probably more realistic. |
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And the platform itself would not have to be a bowl, the capsules could be on davats instead. |
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And the energy saved could be used to power the rotating discs. |
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The power requirements might not be as bad as it seems. The disk rotates at a constant rate, and the trains run at a constant rate, so fewer losses from starting and stopping. |
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As a New Yorker I like any idea that means a faster train ride. |
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[xaviergisz] My idea is different because it is computerized. <wink> |
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Actually it is a bit different because different capules would go to different stations. |
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Thanks for the links though. It is interesting that the Brooklyn Bridge was considered antiquated over a century ago. |
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//affect poeple panhandling or muggers waiting for you in the train?// |
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Yeah - think of people's careers here! |
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A while ago I did a project on trains, and in a book I have I found a curious side-box said that an experiment had been made in which a train never actually stopped, it just slowed to a crawl so as that passengers could get on and off. The experiment was never repeated. |
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It does not elaborate the reasons as to why it was never repeated, whether it was proven to be too dangerous, a lack of funding or interested parties, or just that it was a Bad Idea. |
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I shall endevour to find the book which printed this, so for now I shall remain neutral. |
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This actually all seems entirely feasible if hippo's calcs are right. This should only cause .45 horizontal Gs. |
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//Stopping and starting subway trains takes a lot of energy// |
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//water-based amusement park rides// |
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High speed waterslide subway entrances/exits. |
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[zevkirsh] The pod is going to stop at one and only one station. You walk into your originating station look for a capsule with your destination marked on it, and climb in. |
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If you see a shady person in that capsule, look for another one with the same destination, and use that instead. |
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Also at times other than rush hour I think that someone inside the car should be able to control the door. So if you are the only person in the car, just close the door to keep the muggers and panhandlers out. |
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This works until some bum holds the door open, hoping for a tip, as the train pulls away from the station, and fall out of the train at 94mph. |
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The capsule will not load onto a train unless the door is securely closed. A couple Electronic "Something is blocking the door" announcements and an announcement to a central security/repair depot if that does not work. |
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[bigsleep] Costs $.50 extra. |
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I had a similar idea that it looks like i deleted. My idea was an S shaped station where you would transfer from a fast train to a slow train. |
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I think I deleted the idea due to the calculations some other baker smarter than me did showing me the actual diameters and speeds possible for such a thing. |
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I'm very much impressed w/ all of your success! (+ on being the one thing interesting & possibly feasible enough to make me break down & post when I've banned myself from that for awhile (I have no self discipline do I?)). |
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Make the wheel big enough, say 10km, and you don't need the train... |
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The cost to retrofit every station into a giant wheel would be crazy. How about installing 2-3 moving sidewalks on the station platform. They run parallel to the train and each "layer" of moving sidewalks would be progressively faster as you get closer to the train. The train only needs to slow down to match the speed of the fastest sidewalk, which people can get in and out of in about the same 15-20 sec that the doors normally stay open (at least the DC metro). That should be enough time to exchange passengers before the fastest sidewalk makes it from one end of the platform to the other. |
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a) Here at the halfbakery, inconcievable expense has never stopped us before.
b) Disappearing on us [Zimmy]? |
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phrancis : that's a much nicer improvement on the idea. Takes less space, even more cool :-) ... especially when you think of all the grandmas who were not able to make it to the train in time and are "conveyed" into a wall at the end of the platform at 100 km/h ... unless there is some kind of a safety net that picks up the people who have reached the danger zone. |
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seems like no one has realised the major advantage this system brings: since there are only 4 passengers per cart, it means there won't be any terrorist attack threats on subways. [+] |
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Not so fast: a little damage at the centre bearing should do the trick... |
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<semi-drunken passenger>"Picadilly Circus? I wanted Charing Cross... damned Coriolis effect." |
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Yeah, coffee cups would need to be designed with a sloping top edge. |
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ixnaum: Well, yeah the moving sidewalk wouldn't just go straight into the wall at the other end of the station. That would just be some cruel/funny form of darwinism. There would just be a decelerated sidewalk and padded wall at the end. |
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How about just one sidewalk that gently accelerated to the speed of the slowed train. You would just signaled to get onto that sidewalk if you wanted to catch that particular train. Its like "catching your sidewalk" instead of catching the train - hence the train would never have to stop and the sys would move more commuters in a given time. |
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I love it! One of the many great ideas that would improve the nyc system yet won't be implemented in our lifetimes because they're still working out how to keep the existing system half functional... |
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wasn't the accelerating-sidewalk idea baked by the japanese ? |
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What Galbinus_Caeli has added to this old idea is the use of small carts to accellerate up to train speed. If you combine that with phrancis' modifcation of using conveyors instead of a wheel, then people can accellerate onto and off the train in a deterministic path and no one can fall off and get hurt. |
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Really, since you're using carts, you don't need a wheel or a conveyor belt. A single accelleration rail curving from the boardwalk to the moving train would do the trick. Each cart should be as small and hold as few people as possible. |
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Part of the idea of the giant wheel is that everything keeps moving at a near constant velocity (expect for the passengers). Plus its cool. |
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"Professor Einstein, does New York stop at this train?" |
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I just had the same idea today. [+] One
issue though, even if the g's were bearable
on the edge of the rotating platform,
something would need to be done about
the wind... At 94mph (150km/h) you'd
need at least a pair of safety goggles for
stepping on and off! |
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If starting and stopping and energy lost
during is the only problem.. why not use
regenerative braking? the conductors
know when they have to start applying the
brakes, so it need not be as sophisticated
as for with street vehicles. |
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no new tunnels built, although I like the
capsules idea. |
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Regenerative braking is only about 30% efficient. Then storing that energy is no more than 75% efficient. Then converting that stored power back to movement is no better than 50%. All of which means you only get about 10% back from regenerative braking. Better not to slow down in the first place. |
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You could just go with hills. Trains drive up a high hill that's been designed to absorb all of the kinetic energy into potential energy. People get on/off, then the train zooms down the hill. |
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I like the hills idea. It would allow the train
to stop, but still store the kinetic energy,
efficienty, only losing out to friction, but
only little energy i suppose. |
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Although I've never been on a train before.
Hawaii no more trains. |
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Most subways are usually pretty much flat. They just make the stations deeper as needed. |
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So, not a 24/7 sandwich shop?
//wasn't the accelerating-sidewalk idea baked by the japanese // Dunno about Japan, but I think there was an accelerating travelator at Schipol in the 80s. |
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This reminds me of that fine film, Dark City. There was a train in that one. Poor Keefer was much misused, but the atmosphere and creepy premise made for a fun watch. |
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Great idea, but we need to add one thing. The stations and "trains" have air locks, and the whole tube is de-pressurized to eliminate air resistance. |
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Install a paternoster so that you can have a non-stop elevator as well. |
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[+] Would be nice if we had a service capsule. |
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It seems to me that each station should have two discs. Each
train passes by one and then the other. The first one unloads
capsules from the train and the second one loads capsules
into those now-empty slots. Each disc unloads trains going in
one direction and loads trains going in the other direction. |
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Alternatively, an underground set of ski-lift type
devices could be remarkably simpler, if not quite as
safe... |
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