Painted black with white lettering this 50’ flat car was built by B&O at DuBois, PA, with underframes provided by Greenville Steele Car Co. It was built in the first of two groups, (8400 - 8499 in 1953-54, and 8900 - 8979 in 1955) and classed P-31 (new class F-15). A couple differences between the two groups was flooring and dimentions. Subclasses of these cars were created for various special assignments.