one question that has been on my mind for a while is what were all of the extra but diffrent lites used for on the Southern Pacific Locomotives?? such as the trash can beam lite, 5 set head lites, low hood and high hood 3 set lites. Why did they always have at least one head lite with a red lenz?? What point did they serve for them did this have to do with emergencys??
The red ociliating light comes on when there is an emergency application of the brakes, to warn other trains that there may be danger. I believe oncoming trains view this as a "stop and proceed" signal. Not sure about that one. The other lights are the "Mars" ocilating light. That is a beacon the sweaps in a figure eight motion to warn persons on or near the track. Invented by the same man who's name is on Mars candies. Then there is the standard headlights.
I hope this helps.