Once a car is stationary, what must be ensured by the operator before disengaging the brakes?

Ensuring that the air brake system is charged and the brakes are applied is crucial before disengaging the brakes of a stationary car. This step is essential for maintaining safety and operational integrity. The air brake system relies on compressed air to function effectively; if the system is not charged properly, it may not engage or release as expected, which could lead to the train moving unintentionally.

Applying the brakes while the train is stationary ensures that it remains secured in place, preventing any accidental movement that could cause accidents or jeopardize safety. By confirming that both conditions are met—charging the air brake system and having the brakes applied—an operator can proceed with disengaging the brakes with confidence that the train is stable and under control.