I just got back from apartment hunting and was wary of places too close to the tracks as well. I'm sure the UI undergrads on here can speak to this better, but the tracks are for freight trains that seem pretty active. I managed to ask a girl walking out of an apartment building near the tracks how bothersome the noise was, and she said that the trains go through late every night, and blow their whistles (eek!). She was apparently woken up every night for about the first two weeks she lived in the apartment, and then got used to it.