Door that automatically closes after use.

• A. Self-Closing Door
• B. Runway Enclosure
• C. Periodic Inspection
• D. Pressure Test

Answer: (A)

The main safety concept is a door that automatically returns to the closed position after someone passes, so the barrier remains intact and access to the escalator or moving walk machinery isn’t left open.

A self-closing door is designed to automatically move back to the closed position, typically driven by a spring or hydraulic mechanism. This ensures that after each use the doorway remains protected, reducing the risk of someone entering the machinery pit or coming into contact with moving parts. It’s a practical safety feature required to maintain enclosure and prevent hazards.

The other options describe different things: a runway enclosure is the overall guarded area around the runways, not the door’s action; periodic inspection is about inspecting equipment on a schedule; a pressure test is a method for checking pressure-related systems. None of these describe a door that automatically closes after use.