 Western Pacific received ten GP20s with high short-hoods and dual control stands, thereby facilitating running both long-hood forward and short-hood forward.While the EMD SD24 with six axles was producing with an engine of the same displacement ( per axle), the four axle GP20 was limited to ( per axle) by the capabilities of the traction motors and the direct current traction generators of the time.In appearance the locomotive was similar to a late version GP9 or GP18 (i.e., often with a low short hood, but with the two exhaust stacks over the engine replaced by a single stack forward over the exit of the turbocharger, in common with later turbocharged EMD locomotives.