How far apart are the stations for measuring Vmax according to FRA guidelines?

The correct distance for measuring Vmax according to FRA guidelines is indeed 15.5 feet. This specification is important as it ensures consistency and accuracy in the measurement process, allowing for reliable assessments of train speeds. The selection of this distance is made to strike a balance between practical measuring techniques and ensuring that the readings taken can capture the necessary data while minimizing any potential errors or environmental factors that could affect the outcome.

Understanding this distance is crucial for compliance with regulatory standards, as it directly impacts safety protocols and operational efficiency. In practical terms, using an established interval like 15.5 feet allows for a systematic approach in evaluating train velocities, which is essential for maintaining safe and effective rail operations. This distance aligns with standardized procedures broadly accepted in the rail industry, ensuring that all measurements are comparable and meet the regulatory requirements set forth by the FRA.