What action is required if a train is more than 12 hours late regarding Form L?

When a train is more than 12 hours late, the appropriate action is to annul the Form L. This is important because the Form L, which serves as an authority for train movement, becomes outdated and ineffective when a train is significantly delayed. Annulling the Form L allows for the proper management of train operations and ensures that any new instructions or schedules can be effectively communicated and adhered to.

In this context, the action of annulling helps maintain operational safety and efficiency by preventing confusion that can arise from having a Form L that no longer applies due to the extensive delay. Proper protocol demands that any outright annulment is done to reset and clarify the situation, thereby allowing for the establishment of new operational directives that account for the current state of the train schedule.