I'm trying to identify the airhorn the UP used on the old GP35's ... I understand this was one of the first attempts to mount the horn behind the cab. But I'm not certain what horn was used... a K3? Any help or additional knowledge here would be greatly appreciated. Thanx Andy
"UP used to have the Leslie S-3L on everything, but in recent years they have been buying the Nathan (AirChime) K-3HA." https://utahrails.net/up/up-loco-features.php That's about the best I can find.