These cars were built in 1946 for Southern Pacific, and in 1955, painted in the Southern Pacific Overnights paint scheme – an all-silver car with black ends and daylight orange SP herald. These fast freight cars were seen in use throughout the 1960s. Southern Pacific was a Class 1 railroad from 1865 until 1996, when it was absorbed by Union Pacific after falling on hard times financially in the 1970s and 1980s.