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. William A. Raia captured this view of No. 9402 at McKees Rocks, Pennsylvania on August 27, 1949 in a photo acquired through eBay.
These powerful engines were painted a deep olive green that soon faded to black under the gritty conditions of the industrialized environment in which they operated. They were equipped with "smoke consumers" or overfire jets, their intakes visible along the side of No. 9402's firebox; these appliances 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. Despite their late design the A-2s were equipped with friction bearings instead of roller bearings, and with traditional spoked drivers instead of the more modern disc driver centers. They lacked boosters, but were built with a provision for their later installation. For the dimensions of the A-2 class see the commentary for No. 9405 following.