What is necessary for a train to be considered in service?

For a train to be considered in service, it is essential that the conductor has indication in both zones. This means that the conductor must confirm that the train's operating conditions are safe and compliant across both areas that the train will traverse. This encompasses not only the interior of the train but also the external environment, ensuring that signals, track conditions, and any other necessary indicators are operational.

When the conductor receives and confirms indications from both zones, it verifies that the train is ready to proceed safely. This operational check is a critical safety measure designed to prevent accidents and ensure that everyone onboard and along the route is protected while the train is in operation.

The other options, while important to various aspects of train operations, do not encompass the critical requirement of operational checks that indicate a train is fully prepared and authorized to run. For instance, closing all doors is a procedural step that contributes to safety, yet does not determine service status on its own. Similarly, achieving full speed is a performance characteristic but not a prerequisite for being classified as in service. Reporting to the Control Center is part of overall operational communication, but the core necessity for a train to be in service is fundamentally about ensuring the conductor has the necessary safety confirmations across both operational zones.