Why don't US escalators start and stop automatically?

[QUOTE=Name Clever]
Actually saw one in a shopping center outside of Bangkok. My son and I had a lot of fun playing with it. If developing countries even have them, then the US should have them.
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There are a few inside Bangkok, too, although most shopping centers keep them running full time. The old Don Muang Airport used to have them; not sure about our new airport.

I recently started going to the gym and got trained on the tread mill. I was instructed no to stand on the belt during start up to avoid possible injury.

[QUOTE=Alex_Dubinsky]
it’s so much money that no one, except airports, is going to put up an escalator that isn’t almost continuously used. In which case, of course, the auto stop-start doesn’t help much. I’ve seen it once at a Korean airport, tho.
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If that’s true it does seem rather odd that I’ve seen exactly such escalators in hotels, train stations, stores and office buildings all over Europe.

I have never seen let alone heard of these exculators that slowdown/speed up OR even stop. I asked around and know one i know has heard of them either.

[QUOTE=Patty O’Furniture]
Here in DC we have these nifty overheight vehicle signs (something like this) that are supposed to turn on and flash a message whenever a truck might not be able to clear an underpass. The problem is, the height sensors are mounted along the side of the road and quickly get caked with emissions. Result: the sign flashes all the time.
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All the hight sensors here in Melbourne & surrounding areas are just to poles in each side of the road it a rod going between them, then hanging from the road form some chains is a metal bar that makes a loud noise when a truck hits it so that the truck knows it not going to fit. But truckers are able to ring a certain number and find out the best route for them to take around the city with there height.

[QUOTE=Alex_Dubinsky]
That’s a good idea. But actually, the maintanence of the escalator itself is pretty huge. In fact, it’s so much money that no one, except airports, is going to put up an escalator that isn’t almost continuously used. In which case, of course, the auto stop-start doesn’t help much. I’ve seen it once at a Korean airport, tho.
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I didn’t think they where that much to maintain, because everywhere has escalator here. Every shopping center, every train station in the city has them. There are everywhere.

[QUOTE=Santo Rugger]
Finally, it may actually be more efficient to have it run continuously. From an energy standpoint, it takes quite a bit more energy to accelerate a mass than to maintain a steady rate (think highway vs. city gas mileage). In addition, when calculating product life, start up and shut down of a system may be equivalent to an hour or more of operation, requiring higher maintenance overhead (think diesel engines being left to run instead of being shut off, even for stops as long as 20 minutes).
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I can’t imagine that would be the case with escalators; there’s not a lot of momentum, but there’s (presumably) a LOT of friction, which would mean that startup power would not be significantly higher than running power.

[QUOTE=Santo Rugger]
Logistically, when I walk up to an escalator, I start timing my step four to five strides back. If the escalator didn’t start moving until I was only one stride away, the transition would be balky at best.
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This could be easily compensated for with a PIR sensor adjusted to read a few feet ahead.

[QUOTE=Spoons]
I do recall a test project in the Toronto subway years ago–it was an escalator that was stopped, normally. If somebody at the top stepped on it, the escalator would start and go down; if somebody at the bottom stepped on it, the escalator would start and go up. Obviously, this one did start and stop automatically, but I guess the drawbacks outweighed the positives in the test, since I never saw such escalators installed through the Toronto subway and that one disappeared after a year or two of service.
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Interesting that something like that got developed. Would be a good device in a thrill-movie chase scene.

Few things are more off-putting to me than an escalator that does not move at all! It simply does not feel right walking up or down a stopped escalator. The three-story Nana Plaza bar area in Bangkok has an escalator between the ground and middle floors (note how neatly I side-stepped that whole first-floor/second-floor difference between the US and Europe) that is in a perpetual state of disrepair.

[QUOTE=friedo]
Some escalators in the NYC subway system have this feature.

But most of them, in order to save energy, never run at all.
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Seriously? I thought they were just broken.

[QUOTE=friedo]
But most of them, in order to save energy, never run at all.
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Escalator temporarily stairs. Sorry for the convenience. :cool:

RIP Mitch