The Southern Pacific GS-4 is a class of semi-streamlined "Northern" type steam locomotive operated by the Southern Pacific Railroad (SP) from 1941 to 1958. A total of 28 locomotives were built by Lima Locomotive Works (LLW) in Lima, Ohio, with the first batch of 20 built between March and May 1941, and the second batch of eight built between March and April 1942. The initials GS stands for Golden State or General Service.
The GS-4s served as the primary motive power of SP's famous Coast Daylight passenger train between San Francisco and Los Angeles, California, via San Luis Obispo, California. They also hauled the San Joaquin Daylight and the overnight Lark, both of which ran between San Francisco and Los Angeles as well, although the former ran via the San Joaquin Valley and Tehachapi Pass. Some of the GS-4s were first assigned to haul troop trains during World War II.
In the mid-1950s, SP began to modernize their mainline passenger trains with diesel power, and the GS-4s were relegated to haul San Jose-San Francisco commuter trains and general freight trains. By 1956, SP began to retire their GS-4s and all but one were scrapped by 1959. No. 4449 was donated to the city of Portland, Oregon, as a static display during 1958 until being restored to operating condition in the 1970s. It was still operational and was now based at the Oregon Rail Heritage Center in Portland.
The Southern Pacific (SP) GS-4s were built to a similar design of the streamlined GS-3s, although the latter have the mars light mounted in a dual-headlight casing above the headlight in front of the smokebox door, and an all-weather cab. They were built in two separate groups, the first batch of twenty locomotives (Nos. 4430-4449) in March-May 1941 and the final eight (Nos. 4450-4457) in March-April 1942. The GS-4s were capable of reaching , although SP had a speed limit restriction of . They carried the signature SP orange and red Daylight paint scheme.
The GS-4s pulled SP's premier passenger trains such as the Coast Daylight, the San Joaquin Daylight, the Imperial, the Lark, and the Sunset Limited. During wartime and until 1948 some of the GS-4 locomotives were painted black, when they were all returned to their Daylight colors. Some time after that and before 1956 most were painted black again with their side skirts removed for easier maintenance, and were reassigned to the San Jose-San Francisco Peninsula Commute service, freight service, and the occasional San Joaquin Daylight (steam locomotives remained on that train as late as 1956, which made it the last streamliner to be pulled by steam on the Southern Pacific) until they were replaced by diesel locomotives. GS-4 No. 4443 pulled one of the final steam excursions on the Southern Pacific in 1957. A GS-4 pulled its last passenger train in October 1958, and they were all retired by the end of the year.
No. 4449 is the sole surviving GS-4 locomotive and is one of the most recognizable locomotives of all time. It was donated to the City of Portland, Oregon in 1958 and moved to Oaks Amusement Park for static display. During its time at Oaks Park, the locomotive was vandalized and had many of its external parts stolen such as its builder's plate and whistle. On December 14, 1974, No. 4449 was removed from the park to undergo an operational restoration, performed by Doyle McCormack. From August 1975 to December 1976, No. 4449 shared duties with several other steam locomotives pulling the American Freedom Train (that train was pulled by Reading T-1 2101) throughout the U.S. No. 4449 is still operational and since mid-2012 resides at the Oregon Rail Heritage Center in Portland along with other preserved locomotives and rolling stock. Additionally, No. 4449 contained most of its sister locomotives' parts; one of the driving wheels from No. 4437, the pilot truck from No. 4443, and the trailing truck from No. 4450, as evidenced by the numbers stamped on each of the parts. This was made during the SP steam era, whenever No. 4449 and the GS-4s were getting overhauls during recent visits at one of SP's locomotive workshops, the shop crew would have to interchange their parts whether they were missing or still being worked on. The whistle of No. 4450 also survives today.