I have slept near a railroad for several of the last few nights. The first night I was very near the tracks. So here are some tips:

1. Never pitch your tent on the tracks.
2. Even if you obey #1, you still need a vibration-activated flashing light in your tent that says "YOU ARE NOT ON THE TRACKS". That way when the train starts rumbling your way you don't have to jump out of the tent.