There are a bunch of different factors here. Size and speed of the train can have huge impacts on noise levels. Train horns are loud, and carry pretty far. Our house is about half a mile from a train crossing and if we're really paying attention, I can hear the train just rolling down the tracks from inside our house. That's before they blow their horn for the crossing. But we also live in a sparsely populated, flat, rural area so the sound waves have a pretty easy path to us, and there's not a lot of base level noise that might hide the trains. It's also a house built in the 60s, and probably could use some improvements to insulation/air sealing/sound proofing.
So terrain, obstacles in between you and the trains, size/speed of the trains, and quality of construction all come into play with the noise levels.