These "signal lights" or "safety signal lights" were used on some C&NW steam locomotives as well, in fact some GPs and even switchers had signal lights salvaged from scrapped steam, resulting in odd looking headlight casings above the roof line, not unlike some SP road switchers. Other CNW geeps had them factory installed in the hood. I believe they lit automatically if an engine was put into emergency, which certainly provided faster protection than sending a brakeman out ahead with lantern or fusee.
Dave Nelson
No railroad I worked on had these lights. Here is the little I know about them. I don't think they were used as markers for reverse movements. They could be activated by the engine crew manually, or, came on automatically when the brakes were applied in emergency. In some cases they came on when the brake pipe pressure dropped below a certain value, 40 psi comes to mind.
Hopefully, these lights prevented head on collisions and on multiple track lines, they served to warn an approaching train on the adjacent track that there may be an obstruction in it's path, like derailed cars.
Charlie
Cheers, the Bear.
"One difference between pessimists and optimists is that while pessimists are more often right, optimists have far more fun."
The C&NW had a red warning light in addition to the headlight on many diesels. I recently got an Athearn Genesis as-delivered passenger GP7 that has such a light. Although a number of railroads, including SP and DL&W, had lights like these, their use wasn't consistent among the railroads that had them.
I want to program a DCC decoder to reflect the use of this light on the C&NW. So, under what circumstances was it used? Emergency brake application? Rear marker in reverse? Did it oscillate, or was it steady?
Thanks for any help!