Shown as No. 240 before being renumbered in 1936, eight-wheeled switcher No. 7640 poses in Buffalo, New York on July 19, 1933 for the same unknown photographer who took the preceding photo of No. 7271 in Toledo two days earlier. (He was evidently heading eastward at the time.) No. 7640 belonged to class U3b. All members of class U3, which numbered 417 locomotives in 1940 throughout the New York Central System, had 52-inch drivers and 25x28-inch cylinders, giving them good leverage when digging into their yard duties. The U3b class came from Lima Locomotive Works in 1920-21. No. 7640's group carried a boiler pressure of 175 pounds, slightly lower than some of the other U3s, and developed 50,060 pounds of tractive effort. Members of the U3b class weighed in at 219,500 pounds.