In my search for quiet, I often carry a decibel meter around. Amtrak cars, even the quiet cars, have a constant 90 decibel background noise when in motion (measured with a C weighting). It seems like a lot of the train noise is in the low frequencies and the A weighting OSHA uses is the only thing keeping Amtrak out of violation.
Yeah, part of my point was that American train systems are old and awful and noisy. I had the pleasure of riding a smaller Deutsche Bahn commuter train once and the ambient noise had to be in the 50-60 dB range, if not lower.
