What must be done when a Form D restricting a train's movement covers a portion of track within 3 miles of the delivery point?

When a Form D is issued to restrict a train's movement, especially one that covers a portion of track within 3 miles of the delivery point, it typically indicates a critical situation that requires immediate attention. The primary goal of such a restriction is to ensure safety and maintain control over train movements, particularly when approaching areas where operations may be altered, potentially due to work on the tracks, signals, or other factors that could affect the train's progress.

Stopping the train is crucial in this context to prevent any accidents or unsafe scenarios that might arise from proceeding without fully understanding the implications of the Form D. Stopping allows the crew to assess the situation, communicate with dispatch, and receive further instructions, ensuring that they can adhere to safety protocols and accommodate any changes necessary before continuing.

Proceeding with caution—even slowing down—would not be adequate if the Form D mandates a stop, as it implies the need for full compliance with the directive for safe operations in restricted areas. Therefore, halting the train ensures that crew members can obtain the necessary information and make safe decisions regarding the next steps in their journey.