If a brake pipe reduction greater than the limit is needed to control train speed, what action must be taken?

When a brake pipe reduction greater than the limit is required to control train speed, it indicates a potential issue that needs to be addressed. Stopping the train and inspecting the reason for the requirement is critical because it ensures safety and helps identify any underlying problems that may have caused the excessive braking need. This could be due to various factors such as a malfunctioning brake system, an improperly loaded train, or track conditions that may require evaluation before further action is taken.

Taking this step allows operators to assess the situation effectively, rather than risking the integrity of the train and safety of personnel by continuing operation or making adjustments that could compound the issue. Ensuring compliance with safety standards is crucial, and stopping the train allows for a thorough investigation and proper response.