The GS-4 runs on eight massive 80 drivers, 300lbs psi boiler pressure, and puts out a roaring 5,500 horsepower at 55mph, with a maximum speed of 110 mph. The large drivers gave the locomotive a high top speed; the telling mark of a steam engine built for passenger service. The GS-4 was built for the Southern Pacific Railroad by the Lima Locomotive Works and delivered in the early 1940s for the SP’s premier passenger trains, finding its way to the Daylight series of name trains. One of the more unique specifications for the GS-4 by the SP was its Mars light, a necessity with the large amount of grade crossings and fog present on the West Coast. The Mars light, like ditch lights on modern locomotives, was utilized as a warning for grade crossings that a high speed train was approaching, its shifting light patterns serving as an eye catcher in foggy conditions.
“Postwar” black – Like the wartime black, these GS-4’s had rear mounted train number boards but replaced the traditional “Southern Pacific Lines” lettering with the larger “Southern Pacific” on the tender.
Technical Diagrams + DCC Instructions:
- EM13, train number board, and coupler replacement instructions for the GS-4: Download PDF
- Exploded View Diagram of the GS-4: Download PDF
*Specific road number may not be pictured.