The retractable passenger restraining arms must be located within what distance above the platform edge?

• A. 400-600 mm
• B. 600-800 mm
• C. 1000-1200 mm
• D. 800-1,000 mm

Answer: (D)

The height at which the retractable passenger restraining arms are mounted relative to the platform edge is chosen to be high enough to be clearly seen and engaged as a passenger approaches the edge, yet not so high that they fail to intercept in time or interfere with boarding. Eight hundred to one thousand millimeters above the platform edge places the arms at a reachable, practical height for an average adult and aligns with the typical geometry of the platform and edge. This positioning allows the arms to extend over the edge to help restrain a passenger from stepping onto the escalator when it’s not safe, while avoiding tripping hazards or interference with boarding.

If placed lower than this range, the arms could pose a tripping hazard or fail to intercept effectively. If placed higher, they may not engage promptly in time to prevent a crossing and could interfere with other components or passenger flow.