Not sure if this will work, but it did for me. Audio recording of Southern Pacific 4-8-4 4460, said to be pulling the Daylight through Gilroy, California in the 1950s. Engine has been at St. Louis Museum of Transport since 1960. Only air horn used, no whistle.

http://www.trainorders.com/videos/view.php?316es

I have some photos of SP4460 traveling DIT through San Luis Obispo CA in May 1959. I'd gone to the SP yard to photograph the roundhouse, but one of the locals advised me that the "last steam engine to come down the coast" was in the yard. I hustled up the track and got several shots, including some boys on bikes who probably didn't know what a rare moment this was. Of course, nobody would have dreamed that SP4449 and 2472 would some day retrace the same route under steam! One thing that puzzled me during the 1970's (when one informal fan group had to ban 4449 from their weekly slide shows) was how little was said or printed about the 4460. I knew it was reportedly on static display at the Museum of Transportation in St. Louis, but saw few if any photos. Maybe because it wasn't going anywhere, nobody felt impelled to take pix.

Doesn't shock me that air horns only were used.
The few SP engineers I've talked with who ran GS's all said they mostly used the air horns only.
Of course, that drive the fans nuts when 4449 is out on the iron, the public wants to hear a whistle!

I've also been out to see 4460 in St Louis the last time I was there. It's almost in the farthest corner of the museum property, takes a hike to get back there.
It'd take a LOT of work to get her running again!