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.
Carpet noise fastrack.
One trick with fastrack is carpet with a medium high nap it fills the echo chamber base and really cuts down the noise.
Even after doing these things fastrack tends to be a bit louder than traditional track but it makes the noise tolerable.
Fastrack will never be the quietest track but you can do things to help with the noise level.
Homasote absorbs much of the sound that gets through the carpet padding.
I ve run fastrack on carpeting and it s queiter but to me carpet still lets the sound to escape from under the track.
To eliminate all noise look for a rating that is 75 or higher.