05-01-2013, 08:44 AM
Steam locos sometimes had rear-facing headlights on the tender, though this was not a 100% rule. A headlight in the US was (and is) always clear-white. Steam locos could have either or both classification lights and marker lights, which could be either permanent or detachable on the smokebox sides or on the ends of the pilot beam. The tender could have equivalent lights. These are the ones that could have selectable colors. They are much smaller than headlights, and modelers have only recently begun to find ways to light them in smaller scales. A loco running light in the forward direction without a train on the main line would probably have marker lights on the rear of the tender, at least at night, and if the loco were running forward, the marker lights would show red to the rear. The tender rear headlight would probably be off in the steam era. (In late steam, some railroads would have the marker lights built into fairings on the rear of the tender, but before the 1930s, they would probably be detachable.)
In the daylight, though, there could well be just a single red flag on the coupler if the loco was running forward without a train on the main line. A switcher or any loco within yard limits would not use marker or class lights, so this would not apply.
A few railroads, like the Lackawanna, the C&NW, and the Southern Pacific, had auxiliary headlights on the front of the loco that went red if the emergency brakes were applied (called "dump lights" on at least the Lackawanna). This was to warn a train on double track coming in the opposite direction that since the emergency brakes had been applied, there might be derailed equipment behind that loco that could foul the opposing train. However, the dump light was in addition to the headlight and was not normally lit for anything but an emergency situation. Also, there was no dump light on the rear of the tender.
I recognize that European diesels and electric locos display red tail lights that are larger than red markers on the rear in the US, but the US rules are somewhat different and not consistent.
In the daylight, though, there could well be just a single red flag on the coupler if the loco was running forward without a train on the main line. A switcher or any loco within yard limits would not use marker or class lights, so this would not apply.
A few railroads, like the Lackawanna, the C&NW, and the Southern Pacific, had auxiliary headlights on the front of the loco that went red if the emergency brakes were applied (called "dump lights" on at least the Lackawanna). This was to warn a train on double track coming in the opposite direction that since the emergency brakes had been applied, there might be derailed equipment behind that loco that could foul the opposing train. However, the dump light was in addition to the headlight and was not normally lit for anything but an emergency situation. Also, there was no dump light on the rear of the tender.
I recognize that European diesels and electric locos display red tail lights that are larger than red markers on the rear in the US, but the US rules are somewhat different and not consistent.