What is the standard whistle signal that a train operator uses to signal car inspectors?

The standard whistle signal used by train operators to signal car inspectors is three short blasts. This specific signal is part of the conventions used in rail operations to communicate essential information without the need for radio or visual signals. Three short blasts convey the message that the train operator is calling for car inspectors to come out and inspect the train. This action is crucial for ensuring that safety checks and procedures are carried out efficiently and effectively before a train departs.

Other signals are used for different purposes; for instance, a long blast typically indicates the approach of the train or an alert for the surrounding area, while combinations of short blasts may indicate other requests or notifications. In this context, the three short blasts are uniquely recognized and standardized among rail operators for this specific communication.