What does a red lantern displayed on the rear of a standing car indicate?

A red lantern displayed on the rear of a standing car serves as a crucial safety signal, indicating that employees may be at work beneath the car. This warning is essential for ensuring the safety of maintenance personnel who might be performing tasks under the car or adjacent to it. By signaling this condition, the red lantern alerts other train operators and personnel to exercise caution and maintain a safe distance, helping to prevent accidents or injuries.

In contrast, the other answer choices either do not accurately represent the meaning of a red lantern or relate to circumstances that are not indicated by this signal. For instance, displaying a red lantern does not signify that the car is empty or safe, that the train is out of service, or that an inspection has been conducted. Therefore, understanding the specific implication of the red lantern is vital for maintaining safety protocols around railway operations.