What is the first step to apply a vertical wheel brake?

To apply a vertical wheel brake, the initial action involves placing the release lever or pawl in the ON position. This action is essential because it allows the brake mechanism to engage correctly, ensuring that the brakes will be applied effectively when the brake wheel is turned.

Understanding this process is crucial for safe train operation; the release lever serves as a switch for the brake's function. If the lever is not correctly positioned to engage the brakes, trying to turn the wheel will not result in the intended braking action, which could lead to dangerous situations.

While the other choices may involve actions related to the braking process, they do not represent the correct first step to ensure that the brakes are applied properly. Proper procedure is vital in railroad operations, and following the correct sequence ensures both safety and efficiency during maneuvers involving the train’s braking system.