What safety feature prevents escalator operation when the handrail is not moving?

The handrail speed monitoring system is crucial for escalator safety because it ensures that the handrail moves in synchronization with the escalator steps. If the handrail is not moving while the escalator is in operation, it can create a dangerous situation for users, who may accidentally catch their clothing or body parts in the gap between the moving steps and the stationary handrail. The handrail speed monitoring system detects this discrepancy and triggers a safety mechanism to halt escalator operation, thus preventing potential accidents and injuries.

Other safety features, like emergency stop buttons and safety sensors, play significant roles in the overall safety of escalators but do not specifically monitor the coordination of handrail speed with the steps. The load limit switch is designed to prevent operation if the load exceeds safe limits but does not relate directly to the movement of the handrail.