What should a train operator do upon hearing one long blast of the tower whistle while operating in a yard?

When a train operator hears one long blast of the tower whistle while operating in a yard, the appropriate response is to stop and await further instructions. This signal is typically an indication of caution, meaning that the operator should not proceed without further clarification on how to safely continue operations.

In a yard environment, the presence of other trains, track workers, or equipment can create hazardous situations. Stopping allows the operator to assess their surroundings and avoid potential collisions or accidents. The operator should then look for communication from yard personnel or other signals before deciding on the next course of action.

Proceeding without stopping could lead to unsafe conditions and violations of safety protocols. Other signals, such as a series of short blasts or checking signals before proceeding, would pertain to different situations or conditions not indicated by the long blast, highlighting the importance of adhering to the specified signals in train operation practices.