DETAILS WEST has the Leslie Horns that come close to what the prototype UP unit had:
AH-326 AIR HORN: LESLIE S-3L, RIGHT BELL SIDE 1 EA. $3.75
"I like my Pullman Standards & Budds in Stainless Steel flavors, thank you!"
Are you looking for a Bachmann part, or will a substitute part do? Details Associates and Details West, among others, sell replacement airhorns. See the Walthers on-line catalog.
I have a GP35 (Bachmann Plus model: Union Pacific #763 to be exact) and need a replacement 3-chime airhorn. Does anyone know where I can get one? I just contacted the Bachmann company service department for assistance but wonder if anyone else knows where a replacement can be found.