A pair of EMD SW1500s trundle through Dolores Yard in Carson, California, on November 3, 1986. Besides the obvious difference in paint schemes (2575 is one of two SW1500s to wear the "Kodachrome" color of the ill-fated SPSF merger, and each of those two units wore different versions of this scheme as well), these two switchers differ slightly in other ways as well. SP 2458 was built in September 1967 (and was only the ninth of 240 SW1500s on the SP system) and had signal lights that protruded from the housings on the ends - earning them the nickname "headache" or "headknocker" lights from the crews. SP 2575 rolled out of EMD's La Grange, IL, factory in April 1970. By that time, EMD's design engineers had figured out how to recess the signal lights, creating a cleaner appearance. But other than the signal lights, SP's SW1500s, built from 1967 to 1973, were more consistent in design than most other diesels built over such a long period.