Re: Markers and class lights

Thanks for the information John. I am referring to the multiple lens classification lamps on each side of the smokebox. So, as I understand it, on a regularly scheduled train, not running as a section, the lamps would not be lighted whether it was day or night. And if the train was an extra or had a following section, the lamps would be lighted, displaying the proper colors, but only at night. In the daytime, those same indications would be by flag. How did they change the colors of the classification lamps? Or were the colors fixed in a given lamp, requiring the switching of whole lamps in order to change the colors?
If a train were running as an extra for instance, did the lamps show clear to the front, side, and rear, or just to the front and sides?