What is interlocking in railway signaling?

What is interlocking in railway signaling?

• A. A manual process for operators to coordinate train schedules.
• B. An arrangement of signals and switches that prevents conflicting train movements by ensuring routes are set safely and cannot be altered without authorization.
• C. A power supply arrangement for electric trains.
• D. A type of communication protocol between trains and control center.

Answer: (B)

Interlocking is a safety mechanism in railway signaling that coordinates signals and track switches (points) so that routes are set safely and cannot be changed while a train could be on the approach. The system locks both the signals and the point positions to prevent conflicting movements; a route can only be established and a signal permitted to show proceed when the interlocking confirms that the path is safe. This means changes to the routing require proper authority and confirmation, so you can’t accidentally alter a setting that would lead to a collision or a train occupying a conflicting track. The other descriptions refer to different things: scheduling coordination is about planning train times rather than how routes and signals are physically protected; power supply arrangements deal with supplying electric trains, not route safety; and a communications protocol covers data exchange between trains and control centers, not the logic that prevents unsafe movements at junctions. Interlocking, by contrast, is the concrete mechanism that ties signals and switches together to enforce safe, non-conflicting movements.

Interlocking is a safety mechanism in railway signaling that coordinates signals and track switches (points) so that routes are set safely and cannot be changed while a train could be on the approach. The system locks both the signals and the point positions to prevent conflicting movements; a route can only be established and a signal permitted to show proceed when the interlocking confirms that the path is safe. This means changes to the routing require proper authority and confirmation, so you can’t accidentally alter a setting that would lead to a collision or a train occupying a conflicting track.

The other descriptions refer to different things: scheduling coordination is about planning train times rather than how routes and signals are physically protected; power supply arrangements deal with supplying electric trains, not route safety; and a communications protocol covers data exchange between trains and control centers, not the logic that prevents unsafe movements at junctions. Interlocking, by contrast, is the concrete mechanism that ties signals and switches together to enforce safe, non-conflicting movements.