Whistles

I didn't want to hijack the other thread on whistles, so here we go with a new one.
Has there been any research into what musical notes were blown by steam locomotive whistles? There are many different sounding whistles, and I think it would be interesting to know if there was any effort to "tune" them to a certain musical chord, or were the various "chimes" set at random?
There was a website some time back run by a whistle collector which had a little information of this kind, but I don't seem to be able to find it any more.
Any thoughts on the subject?
Ed