Final answer:
Standing close to railroad tracks when a train passes is dangerous because the atmospheric pressure change can draw a person towards the train, emphasizing the importance of railroad grade crossing safety.
Step-by-step explanation:
The question appears to address railroad grade crossing safety. Concerning railroad grade crossings, it is essential to understand that standing close to railroad tracks is dangerous when a rapidly moving commuter train passes. The primary reason for this is related to atmospheric pressure changes caused by the train. A fast-moving train will push air in front of it, creating a high-pressure wave. Once the train has passed, there will be a low-pressure area following it. This sudden change can cause a person standing too close to the tracks to be drawn towards the train due to the pressure differential, which is why safety at railroad grade crossings is a critical concern.