What should a train operator do if uncertain about the meaning of a signal?

When faced with a situation where the meaning of a signal is unclear, referring to the manual for clarification is the most prudent action. The manual provides specific guidance on signal interpretations, operating procedures, and safety protocols that are crucial for safe train operations. By consulting the manual, the train operator can ensure they are making decisions based on the established guidelines and standards, which helps to promote the safety of passengers, crew, and rail operations.

In contrast, proceeding with caution might leave too much room for interpretation and could lead to safety issues if the signal indicates a stop or other important action. Stopping the train immediately could create unnecessary risk, especially if it is not warranted by the signal's meaning. Consulting the next available operator might not always provide the most accurate information, as the colleague may not have immediate access to the required information or may not be trained on that specific signal. Thus, the best course of action is to refer to the manual, which is designed to provide clear instructions in such situations.