What action should be taken if the Out of Service indication appears?

When the Out of Service indication appears, it is crucial to follow the protocol of removing the train from revenue service as planned or notifying the Trainmaster. This action is essential for maintaining safety and operational integrity. The Out of Service indication often indicates a malfunction or issue that could compromise safety, performance, or reliability, which could lead to accidents or operational disruptions if ignored.

Taking prompt action to remove the train from service ensures that any potential risks are mitigated, allowing for proper maintenance and evaluation before the train is allowed to operate again. Notifying the Trainmaster also allows for a coordinated response and helps maintain communication across the transportation framework.

The other choices suggest either proceeding with the journey or ignoring the indication, which poses significant safety risks. Automatically notifying the maintenance department without assessing the situation first might not provide immediate safety interventions necessary for passenger and crew safety. Each of these alternatives fails to prioritize the crucial aspect of addressing safety issues proactively.