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July 4th, 2003

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02:17 am - Whee!
Superb BBC news story about a really cool-looking type of fast travelator on trial at a Paris metro station. Essentially you start off on a slow conveyor belt and then transfer to a fast one, before transferring to a slow one again and eventually returning to walking off at the far end.

I've idly considered solutions like this in the past as alternative mass transit solutions. Actually, my version had several (six?) parallel conveyor belts, with the outside belt moving slowly and the inside belt moving at a speed comparable to that of a light rail train. I never managed to work out a really convincing way for people to change speeds, though. Is this one the solution? I don't know, but I'm glad that they're trying it to find out.

Nowhere that I've seen yet has a figure for energy consumption. I'd be interested to know whether this could be used and extended to carry people at greater speeds for longer distances or whether that would prove extremely energy-inefficient compared to a train of some description. Theoretically I suppose that you could extend this from three belts at two different speeds to having five belts at three different speeds, but I'm not sure if the rollers for a (say) 11 km/h -> 17 km/h transfer would work as well as the ones for a 3 km/h -> 11 km/h one.

The safety concerns are interesting. I'd have thought that one way to solve them would be just to get people to sit down in a little cart because you can control carts over the rollers in a way that you cannot control feet over the rollers, but this leads to all sorts of embarkation / disembarkation / returning-the-carts problems. It also reduces the advantage that people used to travelling along a 11 km/h belt can still travel faster by walking along it at (effectively) 11 km/h + overtaking speed.

I also am uncertain about how people transfer from a handhold on a belt at one particular speed to a handhold on a belt at a faster speed - frankly, that part of the operation looks at least as fraught and dangerous as the "changing the velocity of your feet" part, and the changing height of the handhold belts looks unnecessarily exciting. (I was also never uncertain about the downside of the "slides and really long escalators" solution, if you have sufficiently efficient escalators and/or a way to convert kinetic energy back into gravitational energy.)

Despite a few petty nationalist reservations, I hope that this works, that this proves to be cost-efficient and that it can spread around the globe.
Current Mood: tiredtired
Current Music: it ought to be the "weeeeeeeeeeeeeeeee!" song from years ago

(10 comments | Leave a comment)


(Deleted comment)
[User Picture]
Date:July 4th, 2003 04:24 pm (UTC)
What if you were to have several "stops" where the belt ended, enabling you to transfer to one of the faster/slower belts or get off entirely?

It reminds me that I've always wanted a roller coaster or - even better - a water slide with decision points. The whole problem comes when you get people who can't or don't decide whether to go left or right and end up with one leg going left and one leg going right. Impalation wedgie o' doom!

Actually, I've harboured an idea for another sort of fairground ride for 15-20 years now, which is a cross between a roller coaster and a water slide. I bet it must be completely impractical, which is why nobody has ever made it. (Copyright herein explicitly disclaimed, idea granted to the public domain, yadda yadda.)

Imagine, if you will, a hard transparent hollow plastic sphere sized so that people can sit in it. Then imagine a similar but larger sphere. Place the smaller sphere, with a rider within, inside the larger sphere, and float the smaller sphere on some sort of liquid within the larger sphere. Accordingly, no matter how the larger sphere is oriented, the smaller sphere will float so that it will not spin relative to the outside world. (Yesno?)

Then you put the outside sphere onto some sort of slide or track and the rest is very obvious. What I really imagine is that this outside sphere goes down a ski-jump, flies through the air and lands on a lake. (Quite possibly going under the water briefly, but returning to the surface afterwards.) Then an artificial tide sweeps the ball to the edge of the lake where people get out.

I also think that bungee-jump sliding down a suitably long, suitably sharp slide would be much more fun than bungee-jump falling, but that's mainly because I'm a big wimp.
[User Picture]
Date:July 3rd, 2003 11:30 pm (UTC)
Not an original idea, I'm afraid. Asimov describes a mass transit device almost identical to the one you have outlined in his books "The Naked Sun" and "The Caves of Steel" IIRC.
[User Picture]
Date:July 4th, 2003 04:04 pm (UTC)
If it's good enough for Isaac, it's more than good enough for me. :-D
Date:July 4th, 2003 12:22 am (UTC)

cool fast and lethal walkway

speaking as someone that uses it... yes it's lethal. most people completely fail to transfer from the slow to the fast bits without falling over. they have supervisors at the start, big flashing lights to warn you and signs all over the place telling you not to lift your feet or hands up when it gets to the change. of course if you put up a big sign telling people not to do something, what does everyone do? consequently they open it for a couple of days, everyone falls over and then they shut it down again while they work on trying to make it less lethal. this has been going on for as long as i've been in paris (almost a year). the fear sure wakes you up in the morning though. oh and the other really cool thing about it is that the slow walkway vibrates and gives you such extreme foot massages that if you're wearing really thin soled shoes you can barely stand on it.

so there you have it. the ultimate comedy walkway. myself, i think they're missing a big marketing potential - it should have one of those automatic photo things at some point along the trip like they do with big rollercoasters, so you can prove that you braved it...
[User Picture]
Date:July 4th, 2003 01:12 am (UTC)

Re: cool fast and lethal walkway

The t-shirt. Definitely needs a t-shirt.
[User Picture]
Date:July 4th, 2003 04:14 pm (UTC)

Re: cool fast and lethal walkway

Hooray! Thank you for sharing this, O most welcome mystery Parisian, whoever you are.

I've been thinking about this a bit more. Is the slow part just a slower belt or is it made up of a number of rollers? By the look of things, there must be a number of rollers somewhere along the line - at the very least, just before the start of the fast belt. I'm wondering if all the rollers are rolled at the same speed, or whether you have one roller rotating so to produce a tangential lateral speed of 2.2 km/h, the next one along of 2.3 km/h and so on up to 9.0 km/h, thus actually accelerating you as you go. This does mean that the front of your foot will be moved faster than the back of your foot, which has got to be interesting. It would be a nightmare in high heels, for insstance, unless you either leant forward or leant backwards - just not stood neutrally.

I do hope this takes off somewhere because I'd like to try it for myself but wouldn't want to have to go to Paris just to do so.

If the principle really does work, there are applications for my two-dimensional theoretical moving walkway. It turns all into rollers, just the speed of the rollers vary from left to right and you crab-walk along from the slow rollers to the faster rollers very gently.

I bet it would unfortunately be incredibly inefficient and unreliable to have a whole mass of different rollers all operating at slightly different speeds from one another and with (presumably) very little resilience in the case of failure. Wouldn't half be cool, though.
[User Picture]
Date:July 4th, 2003 01:24 am (UTC)
I always find that skipping on and off travelators helps you not to stumble *mental image of Parisian business men skipping through the metro*

Hmmm, it's not going to work now is it?
[User Picture]
Date:July 4th, 2003 04:11 am (UTC)
The Roads Must Roll.
[User Picture]
Date:July 4th, 2003 02:29 pm (UTC)
I've idly considered solutions like this in the past as alternative mass transit solutions. Actually, my version had several (six?) parallel conveyor belts, with the outside belt moving slowly and the inside belt moving at a speed comparable to that of a light rail train.

I feel sure I've read or seen something in which a character (who is known for being boring) describes in tedious detail such a device which he has just invented. However, I can't remember what on earth it was. (And it wasn't Asimov.) For all I know, it could have been a Fry&Laurie sketch.
[User Picture]
Date:July 4th, 2003 04:40 pm (UTC)

Geek factor eight, Captain

Hooray! I am not sure whether I am a great mind thinking alike with this bore, or a fool who seldom differs.

There's a wonderful section about escalators at the ever-fascinating Clive's Underground Line Guides. This discusses the earliest London Underground escalators being of a "shunt" type "where a diagonal barrier forced users off to the side at the end of their ride". I had envisioned that a similar mechanism might theoretically be used to shunt passengers from one speed of belt to another. Admittedly there's quite a difference between being shunted off a belt travelling at 3 mph to a stationary walkway and being shunted off a belt travelling at 18 mph to a belt travelling at 15 mph, but just making the angle of the shunt sufficiently shallow ought to alleviate the problem... oughtn't it?

Hooray for "Bumper" Harris!

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