What is the first step to take if a main reservoir rupture occurs on a PA4 train?

In the event of a main reservoir rupture on a PA4 train, the priority is to ensure the safety of the train and its passengers while following proper protocols. Notifying the Trainmaster is crucial as they hold the authority and responsibility for managing the situation effectively. This step ensures that the right personnel are alerted to the emergency, allowing them to coordinate appropriate response actions, such as arranging for assistance or rerouting operations.

While bringing the train to a stop is a critical action, it is not necessarily the first step in a situation that requires immediate notification of supervisory personnel. Checking air compressor switches or operating from the next cab may be relevant actions later in the response process but would not take precedence over notifying the Trainmaster. Engaging with supervision helps rally the necessary resources and expertise to handle the rupture situation safely and effectively.