The GS-2 had a very different appearance than that of their predecessor, the GS-1. The GS-2s were streamlined and designed by Southern Pacific Company for high-speed passenger service in 1935. They featured a silver smokebox with a cone-shaped single headlight casing, skyline casing on the top of the boiler, skirting on the sides, and an air horn. They retained the teardrop classification lights and whistles of the GS-1. They had 73.5 inches drivers and could develop 4500 horsepower at 55 mph with a maximum speed of 90 mph. The tenders were rectangular and had two independent tanks: a 6010-gallon fuel oil tank, and a 22,000-gallon water tank. Access to the open cab was by two ladders attached to the front of the tender.[4]
They were the first locomotives to receive the silver, black, red, and orange Daylight paint scheme designed by Charles L. Eggleston of the Southern Pacific,[5][6] and were used for the streamlined debut of Southern Pacific's premier passenger train, the Coast Daylight, in 1937. The following year they were replaced by the improved GS-3 engines. During World War II, they were painted black and silver and were used to transport troops. In the 1950s their side skirting was removed for easier maintenance, and the locomotives were assigned to general service, such as the San Jose-San FranciscoPeninsula Commute service, the "Coast Mail" trains, and freight service.