What must be done if a hand brake is applied to determine operational brakes in a locomotive?

To determine the operational status of the brakes in a locomotive when a hand brake is applied, it is crucial to observe the pistons at the end opposite to the hand brake. This observation allows the conductor to assess whether the air brakes are functioning properly since the application of a hand brake can sometimes lead to confusion about the overall state of the braking system. By checking the pistons, one can confirm if the air brakes, which operate using compressed air, are responsive and effective despite the hand brake being engaged.

This process helps ensure that both the hand and air brakes are working in unison. It’s important in maintaining safety and operational efficiency on the railroad. Observing the pistons can reveal if there's a lack of movement or any malfunction that could indicate issues in the braking system that may not be related to the hand brake.