Some of my engines are silent conventional. Diluted matte adhered ballast in my experience with two rail track over cork, over 1/2" Homasote, over 3/4" Birch plywood supported every 16" makes for loud running here. I will not be adhering any additional ballast. I may experiment with loose ballast. It's fair to say I hate platform noise originating from the trains. Some of the worst offenders are plastic road bed ready track. When there is sound I prefer a scale level.
My three rail trains are run at about 30 scale MPH which quiets the sound levels.
On the other hand, with traditional tubular track there is a nostalgic value to the crass sounds of loud trains, it's just hard for me to hang around all that noise for any length of time.
