Why Do Escalators Have Those Strange Brushes on the Sides?
If you’ve ever ridden an escalator, you may have noticed a small but curious detail: the strange brushes that run along the edges of the steps, right next to the side panels. Most people ignore them, thinking they’re just a design quirk or a way to make the ride look more “modern.” But those little brushes are not just decoration—they play a critical role in safety, maintenance, and even psychology.
Let’s take a deep dive into why escalators have these brushes, how they work, their hidden benefits, and what happens when they’re absent. By the end, you’ll see your next escalator ride in a completely new light.
The Mystery of the Escalator Brushes
When you first notice them, you might ask:
Are they there to clean shoes?
Are they just decorative?
Or maybe they’re to stop people from stepping too close to the edges?
All of these guesses are partially correct, but there’s more science, engineering, and history behind them than most people realize.
Officially, these brushes are called “skirt brushes”, a term derived from the skirt panel, which is the side panel of the escalator where the steps meet the wall.
A Quick History of Escalators
Before we understand why the brushes exist, it helps to know a little about escalator design.
Invented in the late 19th century, the escalator was originally more like a moving staircase combined with a conveyor belt.
Early designs were mostly metal, with few safety features beyond handrails.
As escalators became popular in department stores, airports, and subways, engineers noticed one big problem: people’s shoes, clothing, and even bags could get caught between the steps and the side panels.
This led to the development of various safety features, one of which was the skirt brush.
Primary Function: Keeping You Safe
The main reason escalators have brushes is safety.
When you stand on an escalator, your feet and shoes are sometimes dangerously close to the gap between the step and the side panel. This space, called the “step-skirt gap”, can pose serious hazards:
Shoes can get stuck, especially loose-soled or pointed shoes.
Small objects, like shoelaces or pant hems, can get caught.
Fingers or toes could potentially slip into the gap.
The brushes act as a soft barrier, guiding feet away from the sides.
How It Works
The bristles are angled slightly outward toward the center of the step.
This creates a physical reminder for riders to keep their feet away from the edges.
Unlike a rigid barrier, the brush is gentle—so if your foot brushes against it, it slides over the bristles rather than getting trapped.
Essentially, it’s a psychological and physical safety measure combined.
Secondary Function: Reducing Friction and Damage
Interestingly, the brushes also protect the escalator itself.
The side panels (skirt panels) can get scratched or scuffed by shoes over time.
Brushing against the hard metal could wear down both the shoes and the escalator.
By providing a soft surface along the edges, the brushes reduce wear and tear on the metal panels and the steps. Think of it as a soft buffer zone between human movement and machinery.
Tertiary Function: Cleaning the Edges
Yes, the brushes do a little cleaning too—but it’s not their main purpose.
Dust, dirt, and small debris often accumulate along the step edges.
As the steps move, the brushes gently sweep the debris away.
While they don’t replace janitorial cleaning, they prevent buildup in the critical gap where things could jam the escalator.
So the brush acts as a preventive maintenance tool as much as a safety feature.
Escalator Accidents: Why the Brushes Matter
Every year, thousands of people worldwide experience escalator-related accidents. Common causes include:
Loose clothing or shoelaces getting caught
Children playing near the edges
People standing too close to the skirt panel
Skirt brushes don’t eliminate these risks, but they significantly reduce the likelihood of entrapment.
Studies show that the angled brushes create both a physical and visual cue, making people unconsciously step away from the edges.
Engineering Behind the Bristles
Skirt brushes are more than just plastic strands glued to a panel. There’s real engineering behind them:
Material Choice
Bristles are usually nylon, sometimes with a soft coating.
They need to be durable, resistant to wear, and able to withstand humidity from high-traffic areas.
Length and Angle
Typically, bristles are 2–3 centimeters long.
Angled toward the center of the step, the bristles create a subtle guide that’s felt underfoot without being uncomfortable.
Spacing and Density
Bristles are dense enough to cover gaps but sparse enough to flex under pressure.
This allows shoes to slide gently past instead of catching.
Maintenance
Over time, brushes wear out and must be replaced.
Maintenance workers check for bristle damage, ensuring the safety margin remains intact.
Psychological Effect: Training Your Feet
You might not even notice it, but the brushes also act as a behavioral guide.
When your foot touches the bristles, you instinctively pull it back toward the center of the step.
Over time, riders become conditioned to avoid the edge, reducing the risk of entrapment.
In other words, it’s not just a physical safety feature—it’s behavioral engineering.
Why Not Just Make the Gap Smaller?
You might wonder, why not just eliminate the problem entirely by making the gap between the step and side panel smaller?
Gaps are necessary for mechanical tolerance.
Escalator steps move on rollers, and the side panel has to accommodate slight expansion, wear, and vibrations.
Too small a gap could cause the metal parts to rub, increasing friction and risk of mechanical failure.
So the skirt brush is the perfect compromise: it maintains the necessary engineering space while keeping humans safe.
International Standards for Escalator Brushes
Escalator safety is highly regulated around the world. Organizations such as:
ISO (International Organization for Standardization)
EN (European Norms)
ASME (American Society of Mechanical Engineers)
all provide guidelines for skirt brushes. Requirements include:
Brush height
Angle relative to the step
Material properties
Flexibility and durability
Manufacturers follow these standards to ensure consistent safety worldwide.
Fun Fact: Brushes for Accessibility
Skirt brushes also help some people with mobility issues:
They provide a tactile guide for visually impaired riders.
The bristles give subtle feedback, indicating where the edges are without requiring sight.
It’s a small feature, but it makes escalators slightly more inclusive.
The Psychology of the “Edge Brush”
Humans are naturally cautious around edges. Skirt brushes amplify that instinct subtly:
The brush’s texture underfoot is a gentle reminder of proximity to potential danger.
Even if you don’t think about it consciously, your foot adjusts.
It’s fascinating to realize that engineers have designed something so unobtrusive yet so effective in guiding behavior.
What Happens If the Brushes Are Missing?
Some older or poorly maintained escalators don’t have brushes—or have worn-down brushes. That’s when accidents spike:
People’s shoes are more likely to get caught
Small items like coins, keys, or scarves can jam the escalator
Maintenance costs increase because debris enters critical mechanical spaces
Replacing or repairing skirt brushes is a high-priority maintenance task in escalator management.
How to Ride Safely Alongside the Brushes
Even with brushes, safety depends on riders following some simple rules:
Keep your feet near the center
The brushes help, but they’re a last line of defense.Tie loose shoelaces
Avoid long, dangling clothing that could catch.Supervise children
Kids often play near edges. The brushes reduce risk but don’t eliminate it.Avoid leaning on side panels
The brushes are not load-bearing—they guide, not support.
Following these tips makes your ride much safer and keeps the escalator running smoothly.
The Hidden Genius of Skirt Brushes
It’s amazing to think about how a tiny row of bristles can make such a big difference:
They prevent injuries
Reduce maintenance costs
Train human behavior
Subtly clean the escalator
Aid accessibility
All of this comes from a detail most of us ignore entirely.
It’s a perfect example of thoughtful engineering—small, simple, and incredibly effective.
Beyond Escalators: Similar Safety Features
Skirt brushes are part of a broader category of soft engineering features designed to guide human behavior:
Subway platform edge tactile strips
Guardrails with flexible padding
Rounded furniture corners in schools
In all cases, subtle physical cues help prevent accidents before they happen.
Conclusion: Next Time You Ride, Notice the Details
The next time you step onto an escalator:
Take a moment to glance at the sides.
Notice the brushes—soft, unassuming, and easy to ignore.
Appreciate the centuries of design thinking that went into this small, but crucial safety feature.
Those little bristles are more than decoration. They’re a marriage of physics, psychology, and safety engineering. They protect feet, guide behavior, and make one of the most ordinary daily experiences—riding an escalator—just a little bit safer.
So next time you slide your shoes along the moving staircase, give a quiet nod to those humble brushes. They may be one of the most overlooked heroes of public transportation.
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