Originally Posted by dkdkrd:
When did the rr's switch over from swinging, free-clapper bells to stationary air-actuated clapper bells...especially on this generation of diesels? Anyone know? I know they were pneumatic when they started going below the frame on later generation diesels, but I've seen some photos of fairly old (e.g., first gen geeps) diesels that seem to have the nose-mounted stationary bell fitted.
??
I don't think that the railroads switched from swinging bells to fixed bells on diesels. Many of the modern steam locomotives were delivered with fixed bells prior to WWII, but EMC/EMD went with fixed bells from day one. The exception to swinging bells on EMC/EMD diesels would have been by specific customer requirement. For example, some railroads had already removed the swinging bells from their steam locomotives, so they simply shipped those bells to EMD and they remounted them on their new switcher units. One railroad that did such a "swinging bell on diesels" requirement, for example, was Northern Pacific.