What is indicated by a successful illumination of the train operator's indication after an emergency stop?

A successful illumination of the train operator's indication after an emergency stop signifies that the train is ready to depart. This indication confirms that all necessary systems have reset appropriately following the emergency halt, indicating that the train can safely resume its journey.

In the context of train operations, a successful indication often includes checks on various systems, which imply that they have returned to a normal status and are functional for safe travel. This is crucial for ensuring both the safety of passengers and the efficiency of train operations.

The other options can lead to confusion because they address different operational concerns. For instance, while it's essential that systems function correctly, the successful illumination specifically does not confirm that all systems require further inspection; rather, it suggests they are operational. Similarly, while testing brakes is certainly critical in the overall safety protocol, the illumination itself indicates readiness rather than a specific need for brake re-testing. Overall, the main point is that the illumination reflects the readiness of the train to depart, resetting after an emergency scenario.