What is required for a train to reverse movement beyond the limits of the same block?

The requirement for a train to reverse movement beyond the limits of the same block is that it must receive Form D line 2 authority when Rule 251 is in effect. This regulation is in place to ensure safe operations when trains are reversing direction, especially in territories governed by specific operating rules like those in the NORAC.

Form D is an important formal document that outlines conditions and authorizations for train operations. Line 2 specifically pertains to operations that involve movements outside of established blocks, where additional oversight is necessary to prevent potential collisions or safety incidents. This ensures that all relevant parties are aware of the train's movements, thereby maintaining safety protocols and communication standards essential in railway operations.

Other choices may imply different procedural requirements which do not align with the specific authority mandated for such movements under Rule 251. Thus, having the correct form empowers the crew with the necessary authority and procedural compliance to conduct the reversing movement safely and legally.