Pittsburgh, McKeesport & Youghiogheny 2-8-2 No. 9558 of class H-8b appears at McKee's Rocks, Pennsylvania on October 25, 1936 in a photo by Howard Davis. The H-8s all had 57-inch drivers, 26½x30-inch cylinders, and a steam pressure of 190 p.s.i. This class had a locomotive weight of 332,700 pounds and produced 59,690 pounds of tractive effort, to which a booster added 10,300 pounds. Their grate area was 60 square feet, with 4740 square feet of evaporative heating surface and 1085 square feet of superheating surface. ALCo built all the H-8s between 1916 and 1920, with No. 9558's group being delivered in 1917. Some members of class H-8b saw further service in Mexico after 1945; No. 9558, however, was part of a group transferred to the Monongahela Railway in 1948, where she became No. 199.