How do you identify if the train has any air or handbrakes applied?

The correct method to determine if the train has any air or handbrakes applied is by examining the illuminated interior or exterior lights, specifically indicator lights that signal the status of the brakes. Many modern trains are equipped with systems that provide visual indicators to the crew concerning the status of the air and handbrakes. When these lights are illuminated, they clearly indicate whether the brakes are engaged or released, allowing for an efficient and immediate understanding of the brake system's status.

The other methods listed may not provide reliable or clear information regarding the brake status. For instance, listening for mechanical sounds might give some clues, but it is not a definitive method for identifying brake application. Similarly, while a handheld brake tester could theoretically indicate if brakes are engaged, it’s not generally used in practice for a quick safety check. Finally, checking the passenger compartment typically does not provide any direct information about the status of the train's braking systems. Thus, relying on illuminated indicator lights ensures accurate and dependable feedback about the train’s braking systems.