This Is Why Escalator Steps Have Those Grooves

Those patterns do more than just look pretty.


If you shop in malls, work in an office building, or take public transit, chances are you spend at least a small portion of your day riding one of the 35,000 escalators in America and the countless others around the world. According to the National Elevator Industry, Inc., 105 billion people use American escalators every year, although few of us give the rhyme or reason behind their design much thought.

If you've ever looked down on an escalator, you've probably noticed that the steps you're on have vertical grooves running through them. While this certainly adds some much-needed aesthetic appeal to an escalator's metal treads, that's far from the only reason they're there.

In fact, those grooves serve an essential function in the operation of the escalator. When the step you're on reaches the top of the escalator, it disappears in front of you, usually sliding under a ridged yellow lip, called a comb plate, as the steps behind it follow suit.

Escalator comb plate

In order for the steps on an escalator to make it back down from the top to the bottom ad infinitum, however, they need to first flatten. However, to do this safely, any matter that might otherwise obstruct the escalator's operation need to be first swept away, which is the function of the comb plate.

Were the escalator steps to lack grooves, they would be harder to clean effectively, and the gap between the steps and the platform—one eliminated by the grooves and comb plate interlocking—would make it easier for unintended materials, from shoelaces to pieces of paper, to get sucked in. 
Additionally, the grooves give liquid a place to collect, meaning that you're less likely to take an unintentional tumble on a rainy day. On a flat step, the water would simply pool and make things slick.

Once the grooves in an escalator's steps have been combed off, they're good to go, and are threaded back down on a motorized loop to the bottom of the escalator, where they become steps again. And when you want to learn more about the amazing world around you, don't miss these 100 Awesome Facts About Everything.

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