Hi there,
It’s probably silly to think that each train has it’s own signature whistle.
But maybe it’s possible to figure out the train by the sound of it’s engine & it’s whistle?
Curiously, B.
Maybe, in the old days. In today’s production manufacturing of both locomotives and horns I seriously doubt one could tell one EMD SD70 to another.
Yes, when the horn or whistle was manual, you could often tell the engineer if not the train and or engine by the way he did it. There were, and are, numerous horns and whistles with different tone and even chords, that often can indicate the different locomotive on any given road. But today the horn, no matter what the tone or chord, is pretty well computer programmed in pitch, volume, and length of time. About the best you could do today is tell one whistle from another rather than engine or engineer. I could start a long ramble here which would go on for millions of posts on how a certain horn or whistle sounded when blown by any given engineer on any given engine on any given railroad. I would start with DL&W E8 #814 which was different than the rest of the fleet and how some engineers on the MU’s could make the horn whisper at midnight yet cause the baloney to jump off the bread at lunch time. The steam whistle…ah, yes, the steam whistle…that, my I can…
AFAIK each railroad specifies what type of airhorn it will use - three-chime, five-chime etc. etc. - or adds it on it’s own after purchase. I know I live a few miles from the joint/parallel CP and BNSF mainlines from the Twin Cities to Chicago, and you can tell they aren’t all using the same horns. If you were close enough to see them a lot I’m sure over time you could identify the CP ones from the BNSF ones.
Canada years ago (over 50 I believe) passed rules that all diesels had to use the same three-chime airhorn. so they have a sound that’s recognizeable compared to other horns you’d hear on US engines. I believe Soundtraxx now makes an EMD decoder with a Canadian airhorn.
Of course I grew up by a railroad that used Hancock Air Whistles, so they really stood out!
Casey Jones in the early 20th Century, is said to have had a personal whistle that he had transferred from engine to engine. But I doubt this practice survived him by very long. I would think shop crews and their managers would have better things to do than install and remove personal whistles from locomotives.
The same practice pertained to the very senior engineers who were assigned their personal PS-4s by the Southern. (Those were the locomotives which had brass candlesticks and such on the headlight bracket - if the engineer wanted them there.)
Many steam locomotive engineers had distinctive whistle ‘styles,’ which were made possible because the whistle cord allowed the steam valve to be opened part way, all the way, and varied within one blast. A few runners elevated whistle blowing to a high art, and their work was easily recognized even though most hearers couldn’t have named the man responsible.
Chuck
I like to think that whistles are unique to an engine and/or engineer…like a signature, or like the howl of a lone wolf…where it is a language that only other train engineers and possibly veteran hobo’s can recognize. 
Keep in mind in those days an engineer worked an assigned locomotive - it was his personal engine that only he used, sometimes for years. It wasn’t unusual for the engineer to add his own customized whistle. Ornamentation like antlers might be added if he was a hunter; Masonic or patriotic symbols were also common.
Casey’s assigned engine at the time he died was a 2-8-0 that was displayed at the 1893 World’s Fair in Chicago. He apparently got to see it while he was working on the commuter trains running to and from the fair. Somehow he finagled this new big engine to be his assigned as his personal engine. Ironically he was just filling in for an ill engineer on 4-6-0 382 that he died in, although that engine has come to be connected with Casey Jones instead of his regular one.
BTW engineers often had their own assigned fireman (in the South, often an African-American) who worked as a team with only that engineer.
