Southern Pacific Lines Tracing its origin to the 1870s, Southern Pacific’s Sunset medallion could be found on railroad maps, timetables, bridges and even on the nose of E-unit locomotives. Toward the end of the SP days as independent railroad, an updated medallion logo would make a reemergence and be proudly displayed along the side of a few AC4400 locomotives, on newly built 48’ intermodal containers and find its way adorned on the most recently built and subsequently last freight cars ordered by the mighty Southern Pacific.