escalators

An escalator is a moving staircase that transports people between floors in buildings, malls, transit terminals, and other facilities. It consists of a set of steps that circulate along a closed loop, a handrail that travels in sync with the steps, comb plates at the upper and lower landing to deter entrapment, and a fixed truss and balustrade enclosure.

The steps ride on a geared or gearless traction drive and are powered by an electric motor. The drive converts rotary motion into the step chain, which moves the steps along a continuous loop. The handrails are linked to the step movement so the rails and steps move together. Typical escalator speeds range roughly from 0.5 to 0.75 meters per second, with higher speeds selected in high-traffic locations. They can be straight-through or curved and are manufactured in a range of widths to suit passenger demand.

Safety and reliability are central to escalator design. Features include emergency stop devices, anti-rollback and overload protection, step demarcation, safety switches, and automatic braking in case of overspeed or obstruction. Regular maintenance includes inspection, lubrication, cleaning of tracks, and testing of safety devices. Most jurisdictions require compliance with national or international standards for design, installation, and operation.

History: escalators were developed in the late 19th century and entered commercial use in the 1890s. Today they are common in retail, transportation hubs, and large public buildings.