The locomotive that used the whistle. (Canadian National S1b Mikado #3254.)
A picture of Canadian National #3254 (The engine responsible for most of the recordings for the sound effects in the Series 6000 library.), undergoing a maintenance check, while pulling an excursion train sometime in September of 2011.
A picture of the locomotive, when it served it's time on the Gettysburg Railroad in Gettysburg, Pennsylvania. (Circa 1986)
The whistle that heard is in this sound effect, along with the other variants from the Series 6000 library, is a fouled Canadian National 5 chime step-top steam whistle, which was recorded from Canadian National Railway S-1-b class 2-8-2 "Mikado" type steam locomotive No. 3254 in the 1980s. Eventually, it would get replaced by a better tuned whistle, due to the old one being a bit too loud and squeaky.
The site/location where the sound effect was recorded was probably at the Steamtown USA in Scranton, Pennsylvania.
As of now, this sound effect is the most commonly used train whistle sound effect, as it has made a number of appearances across 100+ pieces of media, including instances where the train depicted is not steam-powered.
Clean, Full Length and Unedited Link to the Sound Effect[]
Clean, Full Length and Unedited Link to the Sound Effect
Puppy Dog Pals (Heard once in "The Great Shirt Rescue", "The Lab Four" and "Wrap Party Pups", and twice in "Hissy's Big Day" and "Haunted Howl-oween".)
Dinosaur Train: Adventure Island (2021) (First whistle only, paulstretched and layered over an unknown wheezing sound effect; used for the Dinosaur Train's whistle.)
Legend of the Fist: The Return of Chen Zhen (2010)
Lionelville - Destination: Adventure! (2009) (First whistle only, paulstretched; used as the whistle for the majority of the steam locomotives; most notably on the World Cruiser.)
LEGO City Mini Movies (Heard in "Train Ride" and "Night Shift", despite being dubbed on a diesel locomotive and an electric high-speed train respectively.)
Super Mario Galaxy (2nd whistle only, higher pitch; used whenever a Wiggler becomes enraged.)
Super Mario Galaxy 2 (The 2nd whistle is used in a normal pitch whenever Gobblegut blows smoke out of its nostrils and in a high pitch whenever a Wiggler becomes enraged.)
Tornado Outbreak (Used in a lower pitch in the level "Double Wide Damage".)
CBProductions # (Used when Christopher Biello shouts "Woo woo!" in Visiting The Greenberg Great Train And Toy Show In Wilmington, Massachusetts (Trailer) and can be heard on some Development Streams, Random Roblox Games Streams and whichever stream it is heard in.)
SMG4 Videos (1st whistle only, heard once in a low volume in the background in "Mario's Train Trip", after Mario walks inside the caboose at the end of the train going to "Uniderpal Studios".)
SML Videos (Heard once in "Bowser Junior Pierces His Nose".)