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How do spring brakes differ from the service brakes in everyday use?
- A.They are identical in every way
- B.Service brakes are applied and released many times a trip by air added to chambers, while spring brakes are set mainly for parking and emergencies by air removed from their chambers
- C.Spring brakes are used for all normal stops
- D.Service brakes work only when parked
Correct answer
B. Service brakes are applied and released many times a trip by air added to chambers, while spring brakes are set mainly for parking and emergencies by air removed from their chambers
Why
Remembering 'air on to apply' for service and 'air off to apply' for springs explains almost every air brake behavior and test. That single contrast is the key to the whole chapter.
Manual topic: Air Brakes - Spring Brakes and Parking Brakes · From the Air Brakes practice bank (AB-120).