What action must the train take after passing over a dangerous defect?

When a train passes over a dangerous defect, it is crucial for safety that the train crew immediately notify the control operator. This action ensures that the defect is communicated in a timely manner, allowing the control operator to assess the situation and take necessary measures to prevent potential accidents or further complications. By providing this information, the control operator can relay details to other trains in the area, adjust schedules, and dispatch inspection teams if needed. This communication is vital for maintaining safety on the rail line and for the proper management of the railway system.

In contrast, reducing speed to 5 MPH, performing a full inspection of the train, or proceeding without stopping do not guarantee that proper protocols are followed or that the defect is addressed promptly. These actions may not effectively mitigate risks associated with a dangerous defect and could lead to safety issues if the problem persists unreported. Therefore, immediate notification to the control operator is the most responsible and effective course of action in such situations.