During the Great Depression in the 1930s, the Southern Pacific Railroad (SP) needed more power for their heavy passenger train service.[2][3] They ordered a batch of fourteen 4-8-4 GS-1 locomotives from the Baldwin Locomotives Works between May and July 1930.[1] The prefix GS indicates Golden State.[3] Originally, the GS-1s' operating boiler pressure was 210 psi (1.45 MPa), but would eventually increase to 250 psi (1.72 MPa).[1] The GS-1s were the first SP steam locomotives to have the cylinders connected to the frame in one piece.[1] These locomotives operated on saturated steam for the injector, steam heat, hydrostatic lubricator, power reverser; and superheated steam for the oil-burning equipment, feedwater heater pumps, air pumps, booster, and whistle.[1] They were designed to traverse through curves as sharp as 18 degrees.[1]
The first four locomotives, Nos. 700-703, were assigned to the Texas and New Orleans (T&NO) subsidiary, while the last ten, Nos. 4400-4409, were built for SP's main fleet.[1] The GS-1s were assigned to various passenger trains throughout the SP system, and ended their careers on the San Jose-San FranciscoPeninsula Commute service.
Originally No. 700 from T&NO in December 1952 as SP's second No. 4403 replacement in March 1953.[4] Renumbered again as SP's second No. 4470 in July of that year.[4]
701
May 1930
61391
August 13, 1930
January 20, 1956
Originally No. 701 from T&NO in January 1953, became SP's second No. 4471 in July of that year.[4]
702
June 1930
61408
August 8, 1930
July 9, 1956
Originally No. 702 from T&NO in January 1953, became SP's second No. 4404 in April of that year.[4] Renumbered again as No. 4472 three months later.[4]
703
June 1930
61409
August 7, 1930
February 15, 1955
Originally No. 703 from T&NO in January 1953, then became SP's No. 4406 replacement in April of that year.[4] Renumbered again as No. 4473 three months later.[4]
4400
June 1930
61410
August 23, 1930
March 23, 1954
Loaned to T&NO as No. 708 from 1943 to 1952.[4] Returned to the SP as No. 4470 in March 1953 and renumbered again as No. 4400 in July of that year.[4]
4401
June 1930
61411
August 25, 1930
June 8, 1955
Used for evaluation of various burner arrangements and different usage grades of oil in Sacramento, California in September 1946 until late 1951.[4]