When the Clinchfield needed more 2-8-8-2 Mallets in 1923, they had two earlier classes to take as a basis: either the L-1 built by Baldwin in 1919 after their own design or the USRA standard design built by Baldwin in the same year that was called class L-2. They decided to order ten nearly exact USRA copies, which were now built by ALCO-Brooks and designated class L-3. They were used to haul heavy coal trains over the Appalachian mountains. One suffered a boiler explosion in 1948 and was scrapped. While the L-1 was retired by 1950, the L-3 and their L-2 sisters were only retired between 1950 and 1952. 