The Erie's large H-21 class of Consolidations included 175 members built by Alco's Rogers and Cooke plants in 1904. Originally they had Stephenson valve gears and were not superheated, but many were later rebuilt with larger cylinders, superheating, and in most cases the Baker valve gear. No. 1639, shown here at an unknown location and date, displays the Baker's original configuration, in which the combination lever connects at the valve gear hanger instead of immediately behind the cylinders. As rebuilt, these 2-8-0s had 22x32-inch cylinders, a driver diameter of 62½ inches, and 200 p.s.i. of boiler pressure. Their grate area measured 47 square feet, their evaporative heating surface 2578 square feet, and their superheater surface 521 square feet. They weighed 213,300 pounds and put out 42,127 pounds of tractive effort. Some of the rebuilt engines survived until 1952. The photo comes from the collection of Wayne Koch, but the photographer's identity is unknown.