I live next to the UP North West Metra line in Illinois, and they have established quiet zones on the three track mainline. Each crossing is either separated or protected by automatic equipment, most are protected level crossings. The train operators do not sound a warning for each crossing, but they can and do sound a warning if the circumstances dictate. For instance, when they are North bound and see a South bound approaching the crossing as well. This permits the knuckleheads in their cars and on foot to notice that there is also a train approaching from the opposite direction. They also blow when overtaking another train in the same direction, and at some very busy stations when pedestrians clog the nearby streets and walkways.
