If a train must proceed at Restricted Speed due to cab signal failure, what must be assumed about the failed apparatus?

When a train is required to proceed at Restricted Speed due to cab signal failure, it must be assumed that the failed apparatus is inoperative until repaired. This assumption is rooted in safety protocols that prioritize the well-being of both the train crew and the passengers.

Operating at Restricted Speed means that the train must be prepared to stop within the range of vision and is not allowed to exceed a certain speed limit. Assuming that the cab signal apparatus is inoperative means that the crew cannot rely on it for safe train operation. Making this assumption is crucial because it ensures that the train crew is aware that the system designed to provide signals and information about the track ahead is not functioning, necessitating increased caution.

The other choices suggest scenarios where the signal might be functioning or safe to ignore, which would contradict the principles of operational safety that require full acknowledgment of any equipment failure. Thus, understanding that the apparatus is considered inoperative until repaired aligns with maintaining safety standards and operational integrity.