They're only too loud if you're under them. Maybe if you live right next to it with a real old window facing it as well.
I could hear the elevated Bart line at Daly City station two miles away in Colma, where all the graveyards are.
I'd be interested to know where you find this to be true. I have noticed that BART trains through Rockridge don't make much noise. But the track noise is so bad through Fruitvale, you can hear the trains over a mile away.
Looks like it wasn't that clear, but I was referring the elevated lines in Chicago (El) not BART.