If an alarm sounds when passing a defect detector, what must you do?

When an alarm sounds while passing a defect detector, the appropriate response is to immediately reduce speed to a level that will permit the train to stop. This action is crucial because the alarm indicates a potential issue with the train or the track conditions that could pose a safety risk. By reducing speed, the engineer can better assess the situation, communicate with the appropriate personnel, and ensure the safety of the train, its crew, and any passengers or cargo.

Taking this precaution helps to mitigate risks, as it allows for a careful evaluation of the defect that the detector has identified. It is essential to prioritize safety over speed or efficiency in such situations. The response is aligned with standard operating procedures and safety protocols that aim to protect both the train and the operational infrastructure.