EMD SD50 - History

History

The SD50 was produced in response to increasingly tough competition from GE Transportation Systems, whose Dash 7 line was proving quite successful with railroads. While EMD's SD40-2 was a reliable and trusted product, GE's line included locomotives up to 3,600 hp (2,680 kW) with more modern technology, as well as very competitive finance and maintenance deals. EMD responded throughout the SD50 program by offering discounts on large orders, this was also a response to the slow U.S. economy in the 1980s which cut locomotive orders.

GM-EMD had previously produced 3,600 hp (2,700 kW) locomotives, the SD45 and later SD45-2, but these used huge, 20-cylinder engines with high fuel consumption, and had reliability problems when first introduced. Demand for the 45 series dropped sharply after the 1970s fuel crises. The SD50 used an updated version of the V16 645 used in the SD40-2, uprated to 3,500 hp (2,600 kW) from 3,000 hp (2,240 kW). This proved to be a step too far; the 50 series models were plagued by engine problems which harmed both sales and the reputation of EMD.

The subsequent SD60 model replaced the overstressed 645F engine with a new engine series, the 710G.

The SD50's long hood saw changes from previous EMD models. The overall frame length was increased, and the long hood was made substantially longer. The resistors for the dynamic brake grid were moved from their previous location above the prime mover to a new, cooler location in front of the engine compartment air intakes, where they were more effectively separated from the rest of the locomotives' systems, and also closer to the locomotive's electrical switchgear.