Book 25, Question 40
How does an escalator work?
An escalator is a long staircase on a loop.
Its steps are linked to a pair of chains, driven around by a motor. At the top and bottom, the steps flatten out, so you step on and off easily. The handrail moves at the same speed. Stand in the middle, hold on, keep your shoes tied, and keep your hands and clothing away from the sides.