The reference for locomotives and railcars
Southern Pacific classes GS-1 and GS-2
United States | 1930 | 20 produced
GS-1 No. 4405 in San Francisco
GS-1 No. 4405 in San Francisco
collection Taylor Rush

In 1930, the Southern Pacific used its Mountains as a base and installed a larger firebox, now supported by a two-axle bogie. This resulted in the GS-1, which was intended for passenger and express trains with a driver diameter of 73.5 inches or 1,867 mm and was built by Baldwin. GS stood for “Golden State” or later “General Service”. Ten GS-1 were delivered directly to the Southern Pacific and four to the Texas & Louisiana Lines.

GS-2 Nr. 4415 in January 1937 in East St. Louis, Illinois
GS-2 Nr. 4415 in January 1937 in East St. Louis, Illinois
R.J. Foster / collection Taylor Rush

In 1937 six GS-2s were delivered from Lima. They were almost identical to the GS-1, but had colorful streamlined fairing, making them about 6,000 pounds heavier. The famous GS-3 to GS-5, which had larger drivers, were later built with the same fairing. Since the GS-1 and -2 soon no longer had to pull the fastest trains, they were considered for heavy commuter trains. Especially in the San Francisco area, they had to prove their power in demanding schedules until the second half of the 1950s.

Axle config4-8-4 (Northern) 
Gauge4 ft 8 1/2 in (Standard gauge)
Dimensions and Weights
Wheelbase45 ft 10 in
Fixed wheelbase20 ft
Total wheelbase88 ft 3 in94 ft 0 1/2 in
Service weight442,300 lbs448,400 lbs
Adhesive weight262,000 lbs266,500 lbs
Total weight733,300 lbs821,400 lbs
Axle load67,000 lbs
Water capacity16,150 us gal21,600 us gal
Fuel capacity4,690 us gal (oil)6,275 us gal (oil)
Power sourcesteam
Estimated power4,650 hp (3,468 kW)
Optimal speed47 mph
Starting effort63,230 lbf
Power Plant
Driver diameter73.5 in
Boiler pressure250 psi
Expansion typesimple
Cylinderstwo, 27 x 30 in
Grate area90.2 sq ft
Firebox area356 sq ft
Tube heating area4,502 sq ft
Evaporative heating area4,858 sq ft
Superheater area2,565 sq ft
Total heating area7,423 sq ft
Calculated Values
steam locomotive
last changed: 02/2024

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