The Clinchfield Railroad operated ten L-2 class (#725-734) USRA 2-8-8-2's and ten L-3 copies (#735-744) for pulling and pushing their heaviest coal and manifest trains until the E-class Challengers supplemented them. During the first World War, the United States government put the nation's railroads under the control of a government agency: the USRA (United States Railroad Administration). The lasting legacy of the USRA was a group of standard locomotive designs, which were used by railroads across the country. The locomotives were designed to use a minimum of materials to conserve vital materials for the war effort. To serve as many roles as possible, the USRA created a set of 12 standard steam loco designs.
The first to be delivered was Baltimore & Ohio 4500, a USRA light 2-8-2. This engine is currently on display at the B&O Railway Museum in Baltimore, Maryland. The USRA engines came very late: even 4500 served for only a few months before the war ended; many USRA engines were not delivered until after the war.
The origin of the USRA Heavy Mallet can be traced to the Norfolk'n Western Y2 class of 1918. The Y2s had several major issues in their design which prevented them from being very successful. The N&W, having a large amount of influence in the USRA, essentially used the USRA to fix the Y2. The end result was a very successful Mallet that was made for haulin' coal in the Appalacians. 80 USRA 2-8-8-2s were allocated and built to CC&O, Virginian, and N&W. Copies went to N&W, D&RGW, Clinchfield (CC&O), Interstate, and NP in 1923; the N&W continued revising and copying the design into the 1940s.
USRA Heavy Mallet (2-8-8-2)
Builder: ALCo
Drivers: 57 inch
Cylinders: 39 and 25 by 32 inch
Weight: 531,000 pounds
Tractive Effort: 101,300 pounds
Cost: $92,195 ($1,161,812 in 2010 dollars)