[1] The SD50 was produced in response to increasingly tough competition from GE Transportation, 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 (2,685 kW) with more modern technology, as well as very competitive finance and maintenance deals.

The GM-EMD locomotives that immediately preceded the SD50, the 3,600 hp (2,685 kW) SD45 and SD45-2, used huge, 20-cylinder engines that consumed large amounts of fuel and suffered from reliability problems when first introduced.

This proved to be a step too far; the 50 series models were plagued by engine and electrical system problems which harmed EMD's sales and reputation.

One former SD50 engineer praised the locomotives' wheel-slip control system and dynamic braking power, stating "they were able to give more adhesion than a SD40-2".

[3] Shorter than production SD50s, they were equipped with a special double cab roof for insulation against the hot Australian desert sun in the Pilbara region.

[5][6] In June 2017, 6063 and 6064 were sold to the Chicago, Fort Wayne & Eastern Railroad, 6064 was relocated by Genesee & Wyoming to the Indiana & Ohio Railway and renumbered 5016 and 5017.

[7] The SD50F was a Canadian cowl unit version equipped with a "Draper taper" (inset section aft of cab for limited rear visibility).