The Caltrain (and other trains but Caltrain is more frequent) going by San Mateo is brutal. Their horn is almost constantly on due to the many ground level intersections and they are ear drum busting loud (by regulation no less).
Areas where every level crossing is this good can be designated as quiet zones, but few municipalities want to spend the money on that. Train tracks are usually in industrial/commercial areas; homes near them are, shall we say, not centers of political power.