What is required in order to conduct an Air Flow Method (AFM) Brake Leakage Test?

What is required in order to conduct an Air Flow Method (AFM) Brake Leakage Test?

• A. Controlling locomotive must be equipped with an AFM indicator in increments no greater than 10 CFM
• B. AFM indicator must be in increments no greater than 5 CFM
• C. AFM indicator is optional
• D. AFM indicator must be digital

Answer: (A)

Air flow readings are used to detect leaks in the brake system, so you need a control locomotive equipped with an AFM indicator that can show changes in flow with a resolution no greater than 10 cubic feet per minute. That level of precision provides enough sensitivity to spot leaks without being impractically fine, which keeps the test reliable and repeatable across locomotives. The indicator doesn’t have to be digital; what matters is the reading increments—being limited to 10 CFM or finer ensures you can observe meaningful changes during the test. Making the indicator optional or insisting on a specific digital format isn’t required for performing the test, and while a 5 CFM increment would meet the requirement, stating the maximum allowable increment as 10 CFM captures the necessary standard without adding unnecessary specificity.

Air flow readings are used to detect leaks in the brake system, so you need a control locomotive equipped with an AFM indicator that can show changes in flow with a resolution no greater than 10 cubic feet per minute. That level of precision provides enough sensitivity to spot leaks without being impractically fine, which keeps the test reliable and repeatable across locomotives. The indicator doesn’t have to be digital; what matters is the reading increments—being limited to 10 CFM or finer ensures you can observe meaningful changes during the test. Making the indicator optional or insisting on a specific digital format isn’t required for performing the test, and while a 5 CFM increment would meet the requirement, stating the maximum allowable increment as 10 CFM captures the necessary standard without adding unnecessary specificity.