Norfolk and Western Class A
The Norfolk and Western "A" was a class of 43 simple articulated steam locomotives built by the Norfolk and Western's Roanoke Shops in Roanoke, Virginia, between 1936 and 1950 and operated until the late 1950s. These articulated locomotives were designed hauled both fast freight and passenger trains for the N&W and only one has been preserved, No. 1218.
History
Background
During the mid-1920s, the Norfolk and Western Railway compromises a large fleet of compound Mallet type locomotives reliable enough for heavy freight work. However, the N&W were lacking a suitable locomotive needed to pull fast freight or merchandise trains. After World War I ended, the railroad ordered a second batch of 4-8-2 USRA Heavy Mountain class and assigned them to double head with the 4-8-0 M class locomotives on pulling fast freight trains. While the K2as run well on flat terrain, pulling medium weight freight trains, they lacked the power of pulling heavier freight trains at desired speeds. At the quest of needing more power, N&W built their own class of ten 4-8-2s, the K3s, at their Roanoke Shops in Roanoke, Virginia, during 1926.Although these locomotives were designed for dual service, they were not fully satisfactory due to running gear and counterbalancing issues. The K3s also lack the suitable power of handling timed freight trains over the mountains and with speed limitations inherent of their driving wheels, fell short of speeds on level portions of the mainline. In a vain attempt to upgrade their existing roster during 1928, N&W converted one of its 2-6-6-2 Z1 class, No. 1399, to a four-cylinder single expansion locomotive and classify it as a Z2. Although the starting tractive effort of No. 1399 was higher, the boiler was too small to supply steam for the four high-pressure cylinders and the locomotive was too light to provide adequate adhesion.
Introduction and construction
By the mid-1930s, N&W decided to make plans to design a new heavy Mallet type locomotive needed to eliminate the double-heading of passenger trains and pulling timed freight trains. Upon delivery on the class starting in 1936, starting with 1200 and 1201, they were tested and proved successful. The railroad was satisfied with the class and bought eight more the following year. During testing, N&W officials were very impressed with their performance, as they were capable of pulling 4,800 tons at 25 mph on a 0.5% grade and 7,500 tons at 64 mph on level track. During World War II, the railroad built 25 more "A"s between 1943 and 1944 and finally eight more between 1949 and 1950. They were some of the last mainline steam locomotives to be put into service.The locomotives had a cast-steel frame and Timken roller bearings on nearly every surface. The last five had McGill MultiRol roller bearings in the side and main rods, making them the only articulated locomotives to take such friction-reducing measures. They were assigned to freight service and have pulled slower heavy freight trains as well as fast time freight. They were rated at 13,000 tons of drag freight between Williamson, West Virginia and Portsmouth, Ohio, and could reach speeds up to 42 mph pulling such a load. Between Portsmouth and Columbus, Ohio, they were rated at 5,200 tons of fast freight and could reach 65 mph. On passenger runs, they could reach 70 mph. Over the Kenova District, the railroad increased the "A"'s slow freight tonnage ratings from 13,000 to 14,500 tons. To reduce the amount of stops for water, they ran with auxiliary tenders with capacities of up to 20,800 gallons of water. This also increased gross ton-miles per train hour 31% on the 112-mile Kenova District between Williamson and Portsmouth, Ohio.
In 1952, the N&W tested one of the "A"s and Y6b-class locomotives against a four-unit Electro-Motive Division F7 diesel set. The tests indicated that fuel costs and similar items were roughly the same, and the test was considered a tie. However, diesels eventually won out for lower maintenance and other operational costs. As successful as the class was, diesels eventually replaced them. Retirement started in 1958 and by 1959, all of the "A"s had been retired.