C&O’s Headlight Conversion of SB-WR-2-200s

information and photos furnished byNicholas Longshore

The C&O GP7s used the dual Clear version of the Mars SB-WR-2-200 Light (Mars must have offered a dual Clear lens option on ordering these lights -  as “builders shots” from C&O show both lenses as Clear) mounted above the fixed dual bulb headlight fixture. These were only used for a short period of time (few years). C&O removed these lights and used these lights in order to make fixed headlight units for its SW7s (Nos. 5236-5239). It seems that  out of the 40 Mars Lights (1 on each end of locomotive) from the GP7s (Nos. 5700-5719) only 8 of these (1 for each end of locomotive) were rebuilt into fixed headlights equipped with shop built numberboards. (There may have been some spare units made up as well, however).

These SW7 Mars Light conversions were effected by removing the motor, gearbox, and linkages from the unit. Rectangular cutouts were made on both sides of the case. A 50 W bulb was mounted on the base plate. Brass blocks were used to prevent any horizontal movement of the outer gimbal. These blocks are secured by 4 screws per block (2 on one side/2 on the other). The bolts that go through the bushings from the outer gimbal to the 2 inner gimbals were tightened down “hard” to prevent movement in the vertical direction..

The light unit was wired as a conventional fixed dual headlight. Numberboards were mounted to the case at the location of the rectangular cutouts in an inclined fashion in order to be viewed from the front as well as the sides of the locomotive. The 50 W bulb mounted to the base plate, provided illumination for these numberboards. This bulb is a standard GE – “rough train service” 50 W bulb. It is used for illumination of the running boards, numberboards, cab, and engine room lighting requirements on locomotives.

Nicholas used machined aluminum plates to cover the numberboard rectangular cutouts.

Note the brass blocks at each end