I think I had heard a while ago, and just 2 days ago noticed, Philadelphia's Port Authority Transit Corporation has designated the last car to be a quiet car. There's so much ambient noise on every subway I've ridden, I cant' figure what the advantage of a quiet car would be, especially on the underground part.
My opinion also is that if people would just generally follow common courtesy, and common sense, there'd be no need for quiet cars anywhere.
My opinion also is that if people would just generally follow common courtesy, and common sense, there'd be no need for quiet cars anywhere.