The GS-3 had an appearance similar to the GS-2. The GS-3s were streamlined and designed for high-speed passenger service. Like the GS-2, they featured a silver smokebox with a cone-shaped single headlight casing, skyline casing on the top of the boiler, skirting on the sides, an air horn, teardrop classification lights, and whistles. The only major difference in appearance was the increase in driver size.
They received the orange and red "Daylight" paint scheme. They were primarily used on Southern Pacific's premier passenger train at the time, the Coast Daylight. In later years after being replaced by newer GS class engines, they were painted black, had their side skirting removed for easier maintenance, and were reassigned to the San Jose-San Francisco commute trains, freight service, and made occasional appearances on the San Joaquin Daylight.
No GS-3 locomotives survive.