Has anyone noticed that the handrail speed of the escalator is faster than the escalator itself. Whenever I am going up or down an escalator and rest my arm on the moving handrail, my arm always slowly moves away from my body. If you don’t understand, give it a try next time you’re on an escalator. Place your arm next to your hip and before you know it, it’ll be stretch forward as much as a foot before you have to pull your arm back. Does anyone know why this happens?
I’ve noticed this more on escalators that are broken in another way: if you put any resisting force on the handrail, it stops moving entirely. I’d say that there isn’t enough friction against whatever moves it to move it properly w/o slippage.
I’ve only ever noticed the handrail being slower, if anything.
YUCK!!!
I never touch those things.
They are covered in blood, feces, urine, semen…etc
Blood?
They are? How exactly do you happen to know this?
I have never seen anyone crouching while balancing on the handrail and shitting on it (but it would certainly be an entertaining act). I have never seen anyone with a handrail fetish masturbating and ejaculating on the handrail. Do such people exist?
Referring to the OP: I read about that in a newspaper Q&A column, which is the only bit of information I have about it. It said this is because the handrail is driven by a drive wheel, but since slippage between wheel and rail can vary depending on temperature, air humidity and whatever, it’s difficult to always keep rail and escalator synchronous.
Hm, I think Juliotheman is just worried about people not washing their hands after: taking a shit, having a piss, masturbating or murdering someone and then using the handrail. I guess it’s a legitimate concern.
[/hijack]
I’ve noticed this as well. Here’s what I think is happening. Both the steps and the rail are driven by the same motor, and both are going in a loop. Since the handrail is about 3 feet above the steps, it travels a longer loop so will be going a little faster. This causes the hand rail to get slightly ahead of you.
Well, they are supposed to be synchronized.
Um…well yes…sort of…but the handrail isn’t going faster until it reaches the end where it loops around.
But your missing the point. Just as the peak of the Himalayas is going faster than the bottom, it never pulls away from the bottom!
Well, I’m sure I’ve seen it written somewhere that they start out synchronised, but service wear tends to speed the belt up relative to the steps. Something along the lines of the rail stretching or the rail’s bearings wearing down during service or something. It might even have been here on the SDMB, but I can’t find it now.
Hmm… question #6 on this page suggests a solution… the motor which drives the staris has all the load of the riders, while there’s very little weight on the handrail. Maybe the motor, struggling against trying to accelerate mass and move it upwards against gravity, strains, and is slowed down… like a pump motor is less effective when you try to pump stuff up a hill (compared to, says, up a shorter hill).
So, if the stairs drive slows down under the load, and the rail drive isn’t subjected to the same load, then the rail goes faster.
[/end conjecture]
A crew has been overhauling the units here at work. There’s only one motor to drive the whole thing, steps and all.
The steps are on a chain drive and the handrail is friction driven. So there’s probably slippage in the handrail drive.
I’ll ask the mechanics.
Just spoke to the mechanics. Our units are driven by one motor for the rail and steps. But some newer units have separate motors for each. There’s a speed sensor to keep the two syncronized. If that’s out of adjustment there can be speed differences.
Blood? Hell, yeah. Seen them photos, too. Remember to tie your shoes before you step on an escalator.