EMC participated in the construction of a number of motorized railcars, integrated streamliner trainsets, and experimental locomotives in the 1930s.
Most of these were short production runs (one, two, or four units) that were used by a single railroad.
These consisted of Winton prime movers and General Electric generating, control, and transmission components inside a carbody whose assembly was subcontracted to another manufacturer, since EMC did not commence regular road locomotive production until 1937.
The SC and SW switchers were the first locomotives produced in EMC's new factory after its completion in 1936.
The pre-SC and Model 90 switchers were development design locomotives outshopped in 1935.