In 1941, three of Southern Pacific's Baldwin-built P-10 4-6-2 "Pacifics" were streamlined with skyline casings and side skirts, looking very much like a "baby" GS-4s. Engines 2484-2486 were used to haul the "San Joaquin Daylight," and here we see 2484 leading train 52 as it departs Martinez, on its way from Oakland to Los Angeles (via California's Central Valley) in August 1941.