I ran across MD Whistles' youtube channel surfing around. This may not be anything new but,at any rate its fun to hear the replicas of steam whistles that echo lost locos. I wonder if any of these whistles made their way onto O-guage soundsets? Theres seems to be almost no reason a manufacturer couldn't "get it right".
http://www.youtube.com/watch?v=BnhNPNP64ik&feature=related