The last steam locomotives erected by the American Locomotive Company for service in the United States were the seven 2-8-4s of class A-2a delivered to the Pittsburgh & Lake Erie in 1948. No. 9405, shown above at an unidentified location around 1950, is our representative of this class. The photographer is unknown, but the image comes from my late brother David Leonard's collection.
These powerful engines developed a tractive effort of 67,300 pounds but lacked boosters. Whereas most modern Berkshire type locomotives had a driver diameter of 69 inches, the A-2s rolled on 63-inch drivers more suitable for their duties on the P&LE, which served the steel industry and had heavy coal and ore traffic. They had 26x32-inch cylinders and a boiler pressure of 230 p.s.i., and weighed in at a hefty 436,000 pounds. Their grate area measured 95 square feet, their evaporative heating surface 4275 square feet, and their superheating surface 1880 square feet. They were equipped with overfire jets, visible along the side of No. 9405's firebox, which improved fuel combustion and reduced smoke by increasing the air supply. The device under the running board, between the cylinder and the valve gear frame, is the exhaust steam injector, which rendered a feedwater heater unnecessary. Strangely, despite their advanced design, the A-2s were delivered with traditional spoked drivers instead of the more modern disc drivers. They were painted a deep olive green which soon faded to black under the gritty conditions of the industrialized areas in which they operated.
By the time the P&LE Berkshires entered service, dieselization was already advancing across the New York Central System beginning in the East. As newer steam power was displaced it was being moved westward. By the early 1950s the A-2s had been withdrawn from service on the Pittsburgh & Lake Erie and transferred to former "Big Four" lines in Ohio and Indiana, where they may be seen in the Herron video New York Central, Volume 2. They were retired in 1956 and scrapped the following year, having known one of the shortest life spans of any steam locomotive of modern design.