Fastrack will never be the quietest track but you can do things to help with the noise level.
Carpet noise fastrack.
Even after doing these things fastrack tends to be a bit louder than traditional track but it makes the noise tolerable.
In most cases you need to use an underlayment specifically designed for noise reduction between the carpet and the standard pad.
I ve run fastrack on carpeting and it s queiter but to me carpet still lets the sound to escape from under the track.
I also used 2 layers of snow blanket on my xmas layout and it helps i ve tested carpet padding on my layout with some of the track on the foam board and some on the carpet padding and the difference is night and day.
One trick with fastrack is carpet with a medium high nap it fills the echo chamber base and really cuts down the noise.
50 to 65 percent reduction of noise.