Abstract: The application provides a cast power end frame including a pair of end plates and an outer casing extending between the end plates and defining an interior therein; a crank shaft housing extending between the end plates and within the interior of the outer casing, and a plurality of crosshead tubes, each crosshead tube extending substantially perpendicular to the crank shaft housing, wherein the outer casing, crank shaft housing, and crosshead tubes are cast as a single part comprising steel comprising a carbon constituent of 0.06%-1.99% carbon.