# Escalator speed and handrail **URL:** \ **Category:** Factual Questions\ **Created:** [September 5, 2003, 6:57am UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681 "2003-09-05T06:57:35Z")\ **Posts on this page:** 15\ **Page:** 1
**Author:** ![SoulSearching](https://avatars.discourse-cdn.com/v4/letter/s/848f3c/32.png) [@SoulSearching](https://boards.straightdope.com/u/SoulSearching)\ **Post date:** [September 5, 2003, 6:57am UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/1 "2003-09-05T06:57:35Z")
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? ---
**Author:** ![Nanoda](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Nanoda](https://boards.straightdope.com/u/Nanoda)\ **Post date:** [September 5, 2003, 7:03am UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/2 "2003-09-05T07:03:59Z")
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. ---
**Author:** ![TheLoadedDog](https://avatars.discourse-cdn.com/v4/letter/t/35a633/32.png) [@TheLoadedDog](https://boards.straightdope.com/u/TheLoadedDog)\ **Post date:** [September 5, 2003, 7:27am UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/3 "2003-09-05T07:27:17Z")
I’ve only ever noticed the handrail being slower, if anything. ---
**Author:** ![Juliotheman](https://avatars.discourse-cdn.com/v4/letter/j/3bc359/32.png) [@Juliotheman](https://boards.straightdope.com/u/Juliotheman)\ **Post date:** [September 5, 2003, 7:56am UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/4 "2003-09-05T07:56:24Z")
YUCK!!! I never touch those things. They are covered in blood, feces, urine, semen…etc ---
**Author:** ![green\_bladder](https://avatars.discourse-cdn.com/v4/letter/g/73ab20/32.png) [@green\_bladder](https://boards.straightdope.com/u/green_bladder)\ **Post date:** [September 5, 2003, 10:01am UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/5 "2003-09-05T10:01:38Z")
Blood? ---
**Author:** ![sailor](https://avatars.discourse-cdn.com/v4/letter/s/a587f6/32.png) [@sailor](https://boards.straightdope.com/u/sailor)\ **Post date:** [September 5, 2003, 10:24am UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/6 "2003-09-05T10:24:00Z")
> [@](#): > > \*Originally posted by Juliotheman \* > \*\*YUCK!!! > > I never touch those things. > > They are covered in blood, feces, urine, semen…etc \*\* 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? ---
**Author:** ![Schnitte](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/schnitte/32/9033_2.png) [@Schnitte](https://boards.straightdope.com/u/Schnitte)\ **Post date:** [September 5, 2003, 10:32am UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/7 "2003-09-05T10:32:13Z")
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. ---
**Author:** ![green\_bladder](https://avatars.discourse-cdn.com/v4/letter/g/73ab20/32.png) [@green\_bladder](https://boards.straightdope.com/u/green_bladder)\ **Post date:** [September 5, 2003, 10:34am UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/8 "2003-09-05T10:34:20Z")
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] ---
**Author:** ![kferr](https://avatars.discourse-cdn.com/v4/letter/k/71e660/32.png) [@kferr](https://boards.straightdope.com/u/kferr)\ **Post date:** [September 5, 2003, 11:04am UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/9 "2003-09-05T11:04:20Z")
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. ---
**Author:** ![World\_Eater](https://avatars.discourse-cdn.com/v4/letter/w/f04885/32.png) [@World\_Eater](https://boards.straightdope.com/u/World_Eater)\ **Post date:** [September 5, 2003, 11:32am UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/10 "2003-09-05T11:32:40Z")
Well, they are supposed to be synchronized. > **[How Escalators Work](https://science.howstuffworks.com/transport/engines-equipment/escalator.htm)** > > You probably ride escalators all the time, but do you know how they move, and flatten, and keep the handrail in synch with the steps? Find out exactly what is going on inside an escalator. ---
**Author:** ![Philster](https://avatars.discourse-cdn.com/v4/letter/p/13edae/32.png) [@Philster](https://boards.straightdope.com/u/Philster)\ **Post date:** [September 5, 2003, 11:50am UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/11 "2003-09-05T11:50:51Z")
> [@](#): > > \*Originally posted by kferr \* > \*\*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. \*\* 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! ---
**Author:** ![wolfstu](https://avatars.discourse-cdn.com/v4/letter/w/d6d6ee/32.png) [@wolfstu](https://boards.straightdope.com/u/wolfstu)\ **Post date:** [September 5, 2003, 11:57am UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/12 "2003-09-05T11:57:07Z")
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](http://www.dgs.edu.hk/QEF_Sc/Phy/experiments.htm#Investigation%206) 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] ---
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [September 5, 2003, 12:29pm UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/13 "2003-09-05T12:29:55Z")
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. ---
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [September 5, 2003, 1:55pm UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/14 "2003-09-05T13:55:53Z")
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. ---
**Author:** ![dropzone](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dropzone/32/7515_2.png) [@dropzone](https://boards.straightdope.com/u/dropzone)\ **Post date:** [September 5, 2003, 1:56pm UTC](https://boards.straightdope.com/t/escalator-speed-and-handrail/199681/15 "2003-09-05T13:56:21Z")
Blood? Hell, yeah. Seen _them_ photos, too. Remember to tie your shoes before you step on an escalator.