If you approach a railroad crossing with no train in sight, but you can hear a train whistle, what should you do?

When approaching a railroad crossing and hearing a train whistle without seeing a train, the safest action is to stop at the grade crossing or stop line. This is the correct response because the sound of a train whistle indicates that a train may be approaching, and caution is necessary.

Trains can travel at high speeds, and the sound of the whistle serves as a warning that you should be alert and prepared to stop. Stopping at the grade crossing ensures that you are not in danger of crossing the tracks when a train could be coming, even if it is not yet visible.

The other choices imply varying degrees of risk. Continuing to cross or crossing cautiously could lead to a dangerous situation if a train appears quickly, while simply looking for the train without stopping does not account for the safety precautions that need to be taken when a train may be approaching. Prioritizing safety by stopping provides the best chance to avoid a potential accident.