# How an Escalator Works

A cutaway escalator showing its loop of steps, chains, tracks, drive and handrail\.

By happy\-comet\-e4dcb6b3

Topic: Machines

[Open the interactive Jig](https://ask.jig.com/j/6T5FAf6YHVVF)

## Transcript

### 1. Stairs that climb by themselves

An escalator is a staircase that moves\. Its steps glide up at about half a metre each second, a gentle stroll, so you can stand still and still arrive\. Drag anywhere to turn the model and look inside\.

One escalator can carry around 2,000 people an hour\.

### 2. One long loop of steps

The steps never stop at the top\. They slip under the floor, turn over and ride back down underneath, upside down\. Only about half of the steps are ever where you can stand on them\.

This model has 56 steps in its loop\.

### 3. Two chains pull every step

A step chain runs along each side, like a giant bicycle chain\. Every step is fixed to both chains by an axle, so the chains pull all the steps together\. The steps have no motors of their own\.

### 4. The motor hides at the top

Under the top landing, an electric motor turns a gearbox\. A drive chain from the gearbox turns big toothed wheels, called sprockets, and they pull the step chains around the loop\. Try changing the speed\.

Most escalators move at 0\.5 metres per second or a little slower\.

### 5. Two tracks keep each step level

Each step rolls on two pairs of wheels, and each pair follows its own track\. On the slope the tracks keep the step flat, like a stair\. Near the ends the tracks move apart, so the steps line up into a flat floor\. Follow one step to see it change\.

The steps never fold\. They are solid and only change height\.

### 6. Teeth at the landing

The top of every step has long grooves\. At each end, a fixed comb plate pokes its teeth into those grooves\. The step slides away under the comb, so you simply walk off onto the floor\.

### 7. A handrail that keeps pace

The handrail is a long loop of tough rubber with steel inside\. The same motor drives it, so it moves at the same speed as the steps\. It disappears into the end of the side panel and comes back underneath\.

### 8. Ride like an expert

Now you know the secret: a chain of level steps on a loop, pulled by one motor\. Stand in the middle of the step, hold the handrail and hold hands with little riders\. Step off smoothly at the comb\.

The first escalator ran at Coney Island, New York, in 1896\.