Hey everybody, welcome back to explainacum5. What kind of questions do you always want to ask? Talk about them in a way that's easy to understand. We're your hosts, I'm Tim.
And I'm Kevin. So Kevin, today we're talking about something that everyone can relate to, and that is escalators. We've all written them, and oftentimes, we've probably wondered why they're built the way that they are. So a couple of observations to start.
The first one is, why do the brush type things on the side of the escalator exist? What do they do? Or as some people have called it, the escalator shoe shine thingy on the edges. What do they do?
Well, let me tell you, it's not a shoe shine thingy, that's for sure. So I think you're talking about the hair brush looking things that stretch along the bottom of the escalator where the floor meets the wall, right? Exactly. So what purpose do they serve?
Okay, let me give you three exhalations here, actually. First, it serves as a warning. So the brushes are there to alert you through literal friction against your pants or legs that you are close to the edge. And that way you can avoid getting pieces of clothing stuck in the crack between the side and any of the moving parts.
Okay. Second, as a cover, it reduces the amount of dust and debris that makes its way into the underlying escalator mechanism, which is really important for making sure that it's maintained and safe. And finally, third, some people have said that it can help ground static charges that build up in the escalator during operation. So this whole stair mechanism is suspended by necessity to actually allow for the conveyor like motion.
But the brushes on the other hand are attached to a band of metal, which is grounded. And static electricity, it actually can travel to generally non-conductive materials like nylon. It is then conducted away by the metal band to discharge it into the ground, rather than through the fingertips of you or me as we step onto the escalator. I see.
I believe many escalators also have grounded metal brushes under the floor at the base two, to again, help ground any static charges from building up. Wow, that third reason is when I didn't think of myself before. So here's a second observation that requires some e-liphile explanation. Why are the escalator step surfaces jagged with the comb-like things at the bottom and the top?
Oh, so there is a comb at the top and the bottom that prevents your feet and other loose objects from being drawn in to the escalator's mechanism. You know, it's sad that people have died before this was implemented. The stairs as well as the floor, they want to meet very tightly. And this prevents things such as clothing from getting caught in the mechanism amongst other things.
Escalators move at a constant speed. So a dozen people weigh about maybe a metric ton, a while and a full escalator still moves at the same speed. Escalator does not slow down, even if you add several metric tons of additional load to it. Now, think about it.
Think about what that means in case someone gets in the way of the escalator. The comb is also sensitive to pressure and it will actually stop the escalator if it becomes jammed. So even something as light as maybe an earbud wire is enough to activate the kind of stopping mechanism. Well, that is good to know.
Why do escalator handrails sometimes run at a different speed compared to the escalator floor itself? You're right. That's also another really astute observation. So it doesn't always, but often in older escalators, this happens.
There's kind of the coupling of the handrails and the floor itself. So the handrails, they move faster than the escalator to kind of get ahead of where. Since the belt is only friction driven, it will slow down after some time. And if the handrails move slower than the escalator, they'll actually push the person riding back, you know, which may actually cause them to fall over.
And in some countries, escalator handrails actually have to run a search and percentage faster than escalators itself to pull your point of weight forward. So it's kind of by design, by being just slightly faster, when you grab ahold of them, your weight will be distributed more to the front. And this actually reduces the risk of you falling backwards down the escalator, which is really bad. That's a really cool engineering detail there.
Now, have you ever stepped onto an escalator that has stopped IE1 that is not working? Oh yeah, yeah, it does feel pretty strange, doesn't it? Yeah, so that's my question. Why does it feel so strange when you step onto an escalator or offer one that is not working?
Even though you know what it's like to stay walk upstairs and you know what your body should anticipate. So why is it so odd feeling when you're stepping onto it that's not moving? You know, the brain is so weird sometimes. The answer to that is, your brain itself, it's learned to associate escalators with movement and thus the need to compensate for your balance when you're stepping from the stationary floor to a moving one and vice versa.
So you will find that if you don't look at the ground or at the escalator while stepping on and off, you won't feel that odd sense of vertical. I guess there's also another factor, which is that escalator steps are different sizes to regular steps. And in addition, the steps at the beginning and the end of the escalator aren't all the same size either, which further confuses our brains. That's useful to know.
A final question then, in different parts of the world, you'll find that there is different escalator etiquette. Yes, so you mean things like in the London Underground where everyone politely stands to one side, allowing for a kind of walking line and a standing line? Well, that's exactly what I wanted to talk about and to end this episode with, how much more efficient is it to be organized like that where people stand to right and walk on the left? I think there was an experiment in London that looked into exactly this behavior.
That's right, there was. And actually the results were counterintuitive. You would think walking gets more people through at a busy time, right? But it's actually the opposite.
You mean it was better to have just standing room? How do you explain that? So what happened was they ran a test at this very busy London Underground tube station, the Holburn station, which has a very long escalator actually. And first they allowed you to walk up the left side during the trial and then also tested it where the escalator was standing only.
And here's what happened, when walking was allowed, they observed an average total of 115 passengers per minute. Okay, got it. But the standing only ones knocked that through, but all the way up to 151 passengers per minute. Wow.
So their conclusion from the study was that they could actually improve passenger construction by a whopping 30% by having people stand only. Interesting. Can you explain this? Why does that happen?
When you're walking up one side, you need to space out more. So you can't get as many people on the escalator itself. And secondly, the experiment was run on one of the longest escalators in the London Underground network. So some people actually stopped halfway and didn't walk the full way up.
So there is that caveat with this particular experiment. With a shorter elevator, there might be slightly different results. Fascinating. Next time I'm on an escalator, I'm thinking about it in new ways now that I've listened to this episode.
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