What air brake test is required after doubling a solid block of cars to your train?

• A. Visual brake test.
• B. Inspection of air drier.
• C. Class III Application and Release of brakes.
• D. Full locomotive brake test.

Answer: (C)

After doubling a solid block of cars to your train, you must perform a Class III Application and Release of brakes. This test verifies that when you apply the train brakes, all brakes along the train—especially the newly added cars—apply correctly and do so uniformly, and that they release properly when brakes are released to allow the train line to re-charge. It also checks for proper brake pipe pressure and detects leaks or sticking brakes after coupling. Visual brake tests or air dryer inspections don’t confirm braking performance, and a full locomotive brake test is broader and used in different contexts. The Class III test is the specific procedure required after adding cars to ensure the entire train will brake reliably.