An escalator

An escalator is a transport machine for transporting people, consisting of a staircase whose steps move up or down on tracks that stay the surfaces of the individual steps horizontal.A moving walkway, moving sidewalk, revelator, or moderator is a slow conveyor belt that transports people straightly or on a bigotry in a similar manner to an escalator. In both cases, riders can wander or stand. The walkways are often whole in pairs, one for each direction. Modern escalators have metal steps in a stable loop that moves on tracks. Escalators are typically used in pairs with one going up and the other going down.