Whistle Cords are the rope(s) that are inside the cabs of diesel, electric, or steam locomotives which are used to sound or blow the horn or whistle.
The cords connect to the whistle's valve. The system can be slightly different due to the differences between locomotive types, and with the way the whistle is positioned on the locomotive.
Trivia[]
Diesel and electric locomotives more commonly use handles or buttons and sometimes ropes as opposed to chords.
In some of the steam locomotive instead of cord or ropes it could be handles.