Why are the automatic stop mechanisms designed to trip in case of signal power failure?

The reasoning behind the design of automatic stop mechanisms to trip in the event of a signal power failure is primarily centered on safety. When a signal power failure occurs, it can lead to situations where trains might not receive the necessary instructions to stop or slow down, creating hazardous conditions.

By ensuring that the stop mechanisms trip and the stop arms are in the tripping position, the system acts as a fail-safe. This means that if the signals cannot function properly, the automatic stop mechanisms will activate to halt trains, preventing potential accidents or collisions that could arise from uncontrolled movements. This proactive safety measure addresses scenarios where communication between the signaling system and train operators fails, ensuring that trains will always be halted if there is uncertainty in signaling.

Using automatic stop mechanisms in this way significantly enhances the overall safety of the rail system, making it a crucial component of rail operations in the event of unexpected signal issues.