EMD SW9

The EMD SW9 was a diesel-electric switcher locomotive produced by General Motors' Electro-Motive Division between November 1950 and December 1953. It served as the direct successor to the SW7, carrying forward the same 1,200 horsepower output while incorporating refinements to the mechanical configuration. Construction of the type was not limited to EMD's American facilities; General Motors Diesel in London, Ontario also produced examples for Canadian railroads, with Canadian production running from December 1950 through March 1953. When tallied across both production sites, approximately 786 units went to American railroads and 29 to Canadian buyers, bringing the total number constructed to around 815 units across the entire production run. Among the more unusual variants of the SW9 were the TR5 cow-and-calf sets, in which a powered cab unit was paired with an unpowered booster unit sharing a common control system. Ten such paired sets were assembled, with eight going to the Union Pacific Railroad and two destined for the Union Railroad of Pittsburgh. The Union Railroad additionally acquired two standalone TR5B calf units, making these articulated switcher configurations a notable footnote in the SW9's production history. The SW9's legacy extended well beyond its initial production run. In 1994, Amtrak acquired nine SW9 units from various railroads and contracted the National Railway Equipment Company to rebuild them for continued service. These rebuilt locomotives were reclassified as the SW1000R, demonstrating the fundamental soundness of the original design and its capacity to support extended service lives with appropriate modernization.

The SW9 was powered by the EMD 567B prime mover, a 12-cylinder two-stroke diesel engine producing 1,200 horsepower, driving DC traction motors arranged in a B-B wheel configuration with four powered axles across two trucks. The primary visual distinction between the SW9 and its predecessor, the SW7, was the elimination of the upper hood ventilation grilles that had characterized the earlier model, giving the SW9 a somewhat cleaner hood profile. The underlying mechanical layout otherwise followed the established conventions of the EMD switcher line developed through the 1940s. Toward the end of the production run, EMD introduced incremental engine changes into certain SW9 units. Beginning in October 1953, a number of locomotives were completed with the transitional 567BC engine variant. In December 1953, a single locomotive built for Weyerhaeuser, numbered 305, was delivered with the more advanced 567C engine. This final unit effectively served as a bridge to the SW9's successor model, the SW1200, which adopted the 567C as its standard powerplant.

Models by: Atlas · Rapido Trains