Now at IRM, here at Savage, Minnesota on an excursion in 1968.

http://abpr2.railfan.net/abprphoto.cgi? ... e_MN_d.jpg

Ye gods! I rode that excursion. I loved the 21 (and MN&S in general) because of their "air whistles". Sounded like steam even if they weren't. And those NP heavyweight coaches were amazingly comfortable.

Weren't the MN&S whistles similar, if not identical to the distinctive "air chimes" of the New Haven?

It's called a Hancock 4700--one model has a radar-scope-like shield and another model doesn't--and yes, they're the same as New Haven, Seaboard Air Line, and a couple others. I've never heard of another air whistle being actively used in real railroad service, save for a few Westinghouse models on railbuses and doodlebugs.

Being a native of Rhode Island who grew up watching the New Haven in Providence, the Charles Street roundhouse, Northrup Avenue yard, etc., I recall that New Haven's Alco S1/2/3 switchers had a sort of three-chime air whistle. You could hear them using the whistle to signal to switchmen around Northrup Avenue yard and elsewhere.

I recall they had three-chimes with a very pleasant tone. I am not sure whether they were specifically designed to be used as an air whistle or were steam whistles re-used. I suspect it's the former as a steam whistle generally do not perform well with air blowing thru it.

During my time as a part-time employee (attending college) of the dear, departed Narragansett Pier Railroad in the mid-1960s (now you can guess how old I am) we obtained one of the whistles and installed it on "the Pier's" 65-ton Vulcan diesel No. 40 where it sounded great but wasn't loud enough to warn approaching autos at the several road crossings the Pier had. It was kept but we used the air horns for the crossings and the whistle for local switching moves and signals to the switchman (usually me).

Thanks!