Found this fascinating, as when I became a railfan in the 1970s the Santa Fe had these on their units' cabs, near the whistle (they don't spin, the lights just come on one at a time in a circle) and I was hoping some of them would be preserved: https://www.facebook.com/photo/?fbid=10 ... 7942171029

"Saved these babies from the scrap man, quite literally today. These are Prime Manufacturing locomotive beacons, common on BN and the Soo. They all have associated parts tags with them but only one has writing on it, indicating it came off 9616. Further research today, it appears this particular beacon was removed off of SP GP60 #9616 as these beacons were standard delivery from GMD London Ontario in 1988." Steve Schmolinger, top photo; James Byberg, bottom two photos.