Atchison Topeka & Santa Fe Railway CF7 2500 was built by General Motors Electro-Motive Division as ATSF F7A 343L (one of the railway's freight F-Units) in April 1953. As the 1960s were ending, Santa Fe's aging fleet of freight and passenger F7 units were approaching retirement age. The railway decided to experiment with rebuilding these diesels into freight locomotives, and from February 1970 until March 1978, 233 F7As, F3As and F9As were extensively rebuilt into CF7 freight diesels in their Cleburne TX shops. The first built, ATSF 2649, featured dynamic brakes, but the remainder of the fleet were non-dynamic. 2649 through 2472 (the CF7s were built in reverse numerical order, beginning with 2649 through to 2417) were built with rounded cab roofs (from their F-unit origin), and the remainder (2471-2417) were constructed with a flat cab roof (dubbed the "Cleburne angled cab"). Many round-roof CF7s were later retrofitted with the "Cleburne angled cab". (Bakersfield, California – June 15, 1978)