Agreed, “class lamps” are the night signals so as to indicate that the train is either an “extra” (white-not scheduled in the timetable) or is a scheduled (timetable) train that has one or more following sections (green). Flags of the same colors were used during the day to indicate the same.
Marker lights at the rear of a train primarily indicated that this is the rear of the train. The marker lights themselves make this indication during the day, and at night they would be burning. The DRGW also indicated the use of yellow flags to mark the rear of a train during daylight when marker lamps were not available. During the night, the markers could also be displayed differently so as to indicate the train was in the clear on a siding for a meet with a passing train or running against the current of traffic in double track territory.
Each railroad would modify and change rules as time went by so as to better suite their specific operation or as their own system changed. Earl’s example of doing away with scheduled (timetable) trains on the narrow gauge lines in later years, made the application of the specific rule regarding class lamps unnecessary.
One of the things that I discuss on occasion with other railroad historians, is the loss and absence of the “human element” and understanding of operating practices that are rapidly, if not already disappearing. This includes the understanding of early operating rules, rights/superiority of trains, train orders, etc. IMHO much of this is being lost as the focus seems to be more on the hardware, restoration and operating the equipment and not what railroaders had to understand so as to operate trains and the rules and procedures required to do so. There are getting to be fewer and fewer folks around who really understand how to do this, especially the various differences between the railroads and how they applied the rules. I suggest that all who are interested in how the railroad worked and how the rules apply, take a look at some DRGW Rule Books and Timetable Special Instructions from various times in history. It will give you a great insight into that human element and operation of the narrow gauge.
DRGW Class Lamp (Radial)
Interior with shield covering green lens showing white (extra)
DRGW Class lamp (early round lens)
Interior showing both green and red glass lens covers, depending on extra (white), second section (green) or red (running backwards at night).