To test brake pipe leakage you must verify:

To test brake pipe leakage you must verify:

• A. The airflow indicator shows 60 CFM (or 90 CFM combined while operating DP) or less when using AFM. No more than 5 PSI using other test.
• B. The train is moving at least 20 mph during the test.
• C. The brake pipe is fully charged to 110 PSI.
• D. The locomotive horn is tested beforehand.

Answer: (A)

Testing brake pipe leakage is about measuring how much air leaks from the brake pipe when the system is charged and isolated. There are two ways this is checked. First, you use an air flow indicator (AFM). If the reading is 60 CFM or less, or 90 CFM or less when the locomotive’s dynamic braking is in use, the leakage is within acceptable limits. The idea is that a healthy system should not pull a large amount of air after you seal the brake pipe, so a low flow rate indicates minimal leakage. If you don’t use the AFM method, you perform a pressure-drop check. With the brake pipe fully charged to 110 psi, you isolate the system and observe how much the pressure falls. It must not drop more than 5 psi; a larger drop signals leakage somewhere in the brake pipe or its connections. The other options don’t measure leakage directly: moving the train isn’t part of the leakage test, simply ensuring the pipe is charged doesn’t test for leakage, and testing the locomotive horn has no relation to brake pipe leakage.

Testing brake pipe leakage is about measuring how much air leaks from the brake pipe when the system is charged and isolated. There are two ways this is checked. First, you use an air flow indicator (AFM). If the reading is 60 CFM or less, or 90 CFM or less when the locomotive’s dynamic braking is in use, the leakage is within acceptable limits. The idea is that a healthy system should not pull a large amount of air after you seal the brake pipe, so a low flow rate indicates minimal leakage.

If you don’t use the AFM method, you perform a pressure-drop check. With the brake pipe fully charged to 110 psi, you isolate the system and observe how much the pressure falls. It must not drop more than 5 psi; a larger drop signals leakage somewhere in the brake pipe or its connections.

The other options don’t measure leakage directly: moving the train isn’t part of the leakage test, simply ensuring the pipe is charged doesn’t test for leakage, and testing the locomotive horn has no relation to brake pipe leakage.