If a signal appliance functions improperly, can it be used?

When a signal appliance is functioning improperly, it is essential for safety and operational integrity that it does not allow trains to proceed. Therefore, it must display a Stop indication to prevent potential accidents and ensure that trains do not enter areas that are unsafe or where the signal is malfunctioning.

The Stop indication serves as a critical safety measure, alerting train crews to halt and assess the situation before proceeding. This reinforces the importance of strict adherence to signaling protocols, which are in place to maintain safety on the railway. Allowing a malfunctioning signal to function in any capacity other than signaling a Stop poses significant risk to operations, as it could lead to collisions or derailments due to unclear communication regarding track conditions.