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Moving staircase used as transportation between floors or levels in stores, airports, subways, and other mass pedestrian areas. The name was first applied to a moving stairway shown at the Paris Exposition of 1900. Modern escalators are electrically powered, driven by chain and sprocket, and held in place by two tracks. As the treads approach a landing, they pass through a comb device; a switch cuts off power if an object becomes jammed between comb and treads.
This entry comes from Encyclopædia Britannica Concise. For the full entry on escalator, visit Britannica.com.