Would some knowledgable Forumite kindly address the topic of swinging bells mounted atop the short hood of Northern Pacific GP7's and/or GP9's?
Although I had been aware of this unusual bell application since the 1950's, I finally saw a pair of NP geeps working a local at Yakima in 1971, after the BN merger, but still in black and gold paint. The bells were yoke-mounted, equipped with air pressure ringers, and swung, rather than being stationary with air-powered clappers, as was the more common practice on diesel locomotives.
I'm curious to know whether these bells were applied to all NP geeps (and possibly to their Alco RS3's and RS11's, as well as the Baldwin road switchers), and when they were removed.