Chuck,
I think it had to do with the sand boxes on the SD7s and 9s. The sand boxes were built into the front sheet of both the GP and SD model locomotives, however, those on the SDs were larger and taller, extending to just under the number boards. The basic sand box capacity on a GP7/9 is 18 cu. ft. while on the Q’s SD7/9, they were 21 and 24 cu. ft. The road headlight on the Q SD7/9s was located in the standard EMD position. To lower the road headlight on the SDs similar to the way that the GP7/9s were, would have interfered with the top of the sand box making wiring and maintenance difficult. The alternative was to leave the road headlight in the standard position and raise the Mars light above it. If I recall correctly, the applications were made at EMD during construction and delivered with the Mars light in place. Knowing EMD very well, I am sure that, for a price, they would have mounted the Mars lights in the same manner as the GP units, but the Q might not have been willing to pay the additional charge.
Bill Barber Gravois Mills, MO
Tue Feb 16, 2016 4:34 pm (PST) . Posted by:
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Posted by: William Barber <clipperw@gmail.com>
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