If only a Stop Signal is present, what must crewmembers do before passing?

In rail operations, a Stop Signal indicates that the train must come to a complete halt before proceeding. When crewmembers encounter only a Stop Signal, the correct course of action is to stop the train and confirm that the signal can safely be passed. This procedure ensures the safety of both the train and any personnel or equipment that may be present on the tracks ahead.

Stopping allows the crew to assess any potential hazards, confirm the state of the track, and ensure they are adhering to operational protocols. This process is crucial for maintaining safety in rail operations as it allows for the verification of track conditions and communication with dispatch or other relevant personnel, if needed, before proceeding.

Other options, such as proceeding with caution, confirming visibility with the lead engineer, or calling it a single time, do not adequately address the safety protocols required when dealing with a Stop Signal. Only stopping and verifying the signal guarantees that the crew has taken the necessary steps to ensure they can safely continue their journey without risking an incident.