Under what conditions can Form D line 13 be used?

Form D line 13 is specifically utilized in situations where the limits of the Form D cannot be contained within line 4. This is crucial for ensuring clarity and completeness of the information related to the train's operation and routing. When additional space is needed to accurately convey the limits that are required for safe operations, line 13 serves as a vital tool to extend the necessary details beyond the standard formatting constraints. Hence, its use is justified primarily when the limits surpass the capacity of line 4, allowing for a clear and precise conveyance of operational boundaries.

In comparison, administrative updates or delayed services do not directly pertain to the need for adjusting the limits specified in Form D, and reporting malfunctions typically follows other procedures rather than adjusting limit specifications. Thus, line 13's purpose remains distinctly tied to situations regarding limitations that exceed the standard entry options.