Which device has a mechanical interlock preventing movement when open?

• A. Platform Gate
• B. Interlock Wiring
• C. Call/Send Control Station
• D. Platform Hand

Answer: (A)

The device that uses a mechanical interlock to stop movement when open is the platform gate. A mechanical interlock is built into the gate so that the drive circuit cannot start or will be interrupted if the gate isn’t closed. When the gate is closed, the interlock allows the machine to operate; when the gate is opened, the interlock disengages the drive, preventing the escalator or moving walk from moving. This mechanical linkage is what physically ties the gate’s position to the ability to move, providing a reliable safety safeguard for passengers on the platform.

Interlock wiring refers to the electrical wiring and safety circuits that enforce interlocks, not a specific device that blocks motion by itself. A call/send control station controls starting, stopping, or directing movement, but it isn’t the device that prevents motion when a gate is open. A platform hand is a barrier or guide device, not the interlock mechanism that prevents movement.