What is the first step to take when a penalty brake application occurs?

When a penalty brake application occurs, the first step is to move the automatic brake valve handle to the suppression position. This action is crucial because it helps to reduce the effects of the penalty application, which is often initiated due to a detected problem such as a loss of communication or a dangerous condition in the train’s operation.

By placing the automatic brake valve in the suppression position, the crew can minimize the brake force applied by the penalty application, allowing for more control over the train's deceleration. This step is essential in managing the situation safely and effectively, ensuring the train does not come to a sudden stop, which could lead to other safety concerns or complications.

Other options such as activating an emergency stop system or applying the independent brake may be necessary later, but the immediate priority must be stabilizing control through the suppression position of the automatic brake valve. Notifying the train dispatcher can occur after ensuring that proper initial mitigation steps are taken, while applying the independent brake is a response that may need to follow the initial action of suppressing the penalty application.