Also, as a friend noticed when he bought a ver nice apartment next to the railroad is that they have to (at least in Sweden) maintain the tracks once a month. They do this by going very slowly with a special train that basically runs with the brakes on throwing sparks all over with all the noise you can imagine. And since it's going to slowly, they have to do it when there are the fewest number of other trains running, i.e. at three in the morning.