What action does an operator indicate by blowing three short blasts of the train whistle?

When an operator blows three short blasts of the train whistle, it signifies calling for the car inspector. This action is a standardized communication method within the railway industry, ensuring that personnel on the ground are aware of the need for inspection or assistance. For instance, during the inspection process or when there is a requirement to check specific aspects of the train, this whistle signal is employed to alert the car inspector to attend to the train, ensuring safety and operational efficiency.

The other options pertain to different whistle signals that convey other meanings, such as notifying of a stop, warning of an approaching train, or indicating a signal change, which involve distinct whistle patterns recognized in railway operations. Understanding these signals is crucial for train operators and their interactions with ground staff and other trains, ultimately aiding in safe and effective railway management.