The C&O had a total of 12 4-8-4s, with the first five numbered 600-604 built in 1935, with the designation J-3. In 1942, two more were ordered from Lima numbered 605-606. In 1948, the design changed slightly and the 610-614 were produced, with the J-3-A designation. No. 614 was originally retired in 1952, but three years later, it, as well as No. 610 were brought back into revenue service to pull heavy freight trains in favor of the upcoming freight traffic on most American railroads. While being brought back into service, however, No. 614 was renumbered to 611, since there was a power shortage on the C&O as to alleviate any confusion with some leased 4-8-4s from the Richmond, Fredericksburg and Potomac Railroad, one of which was also numbered 614. The original C&O 611 remained out of service.