We've had this discussion many times before. Class lights are displayed on the front of a locomotive and display either no light, white light or green light. No light means it is a scheduled timetabled train. White light indicates an extra and green indicates that a second section of the same train number will be following.
The model, as shown, is wearing marker lamps, which must be displayed at the end of a train. This would indicated that the engine is a helper, shoving at the rear of the train, behind the caboose. It could be a light engine, running backwards over the line, but the normal method for running a light engine backwards was to have the white flags or class lights in the normal location on the boiler and to put the marker lights on the pilot beam brackets.
How the lights change color on class lights is a separate issue. The famous D&RGW radial lamps have clear lenses and a green filter rotates in behind the glass when showing a second section. Most other styles also used clear lenses and a green filter of some kind when showing green.
Michael Allen
Edited 2 time(s). Last edit at 09/03/2009 08:40AM by trainrider47.