Not all locomotives are equal, electric is much quieter than diesel

Both older DC and newer AC trains are effectively silent when coasting on a straight

The main sources of noise are cornering and braking. I live in a rare city that has narrow gauge for all of our rail, and am less than 200m from the busiest corridor in our state

I regret chosing an apartment on a tight bend (narrow gauge's bends are especially loud)

But if I were to live 500m away parallel to the track (as in, still 200m away from the track) the mostly AC electric trains going by every few minutes would be largely inaudible (<40dB)

My main point is tracks aren't loud, tight corners and areas around stops can be loud

I fear city planners aren't testing their decisions closely enough, though