What is one of the criteria for defining each end of the out-of-service limits?

Defining the out-of-service limits is crucial for ensuring safety and clarity in railway operations. One of the established criteria for determining each end of these limits is the identification of a whole mile post. This is beneficial because mileposts provide clear and recognizable landmarks that can be universally understood by all personnel involved in the railway operations.

Using a whole mile post means there is a specific, measurable point on the railway that can be communicated effectively across teams, minimizing confusion. This also aids in the documentation and reporting of incidents or conditions that affect the operational status of the tracks. Mile posts are typically marked and standardized, ensuring they are consistently used and recognized throughout different parts of the rail network. In contrast, while physical barricades, temporary flagmen, and voice confirmations may all play roles in maintaining safety or mitigating hazards, they do not serve the same foundational purpose in clearly defining out-of-service limits.