Not sure which is which on your video but the locomotive on the right has the "actual" whistle tone from the real Pere Marquette 1225 Berkshire. (I prefer it to the one on the left in your video that IMO sounds computerized)
https://www.youtube.com/watch?v=cyJV0NGVgi8
Having said that. Even though the PM 1225 was recorded for use in the movie. At least as far as the whistle is concerned. They ended up using Sierra Railway No. 3's whistle:
(Not my video)