Built by the American Car and Foundry Company in 1941, APWX #1002 was a depressed center flatcar measuring 43 feet 8 inches long, weighing 180,000 pounds, carrying a capacity of 58,000 pounds, and riding on four axles. Besides serving as a freight car, it was used by the Appalachian Power Company, part of the American Electric Power system, as a railroad mobile transformer and substation. During the early 1940s, five three-phase transformers were installed on the car so that if a power transformer failed or needed maintenance, a mobile substation could be quickly delivered and installed by rail. After railroad spur tracks to power substations were removed, rail delivery of mobile substations was no longer necessary. In 1969, the transformers were removed from this car and installed at the Monte Carlo station near Princeton, West Virginia, and the flatcar was then used to move electric transformers throughout the American Electric Power system. Its lowered center allowed the transport of tall items, and it is the only surviving one of the five depressed center flatcars used by American Electric Power in the 1940s.