Final answer:
After a train has passed, ensure safety by looking both ways along the track and listening for any train signals before proceeding across the railroad tracks with caution.
Step-by-step explanation:
Once a train has passed, before proceeding across a set of railroad tracks, it is essential to take a few precautionary steps to ensure safety. First, you should look both ways along the track to make sure no other trains are coming. This is because there could be another train approaching on an adjacent track. It's also a good idea to listen for any train signals or horns that might indicate another train is near. Once you have double-checked and are certain that no trains are approaching, you can then proceed across the tracks with caution.