How do escalators keep moving?
For grown-ups: the science
An electric motor turns wheels that move linked steps in a loop.
Escalators use an electric motor and gearbox to drive a main shaft and sprockets. A chain system carries the steps in a continuous loop, while a separate handrail drive is synchronized to travel at approximately the same speed as the steps.
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Transcript
Look at the stairs gliding up to the next floor. How do escalators keep moving?
Under the stairs, a motor uses electricity to turn. The motor gives the escalator its push.
Strong linked steps travel around big wheels, like a moving loop. One side goes up while the other side comes back down.
The handrail is linked to the moving steps too. It travels at nearly the same speed, so riders can hold on.
So an electric motor turns wheels that carry the linked steps around and around.