During World War II, the rail mobilization of fighting troops caused passenger miles to quadruple from 1940 to 1944 as troops were carried to embarkation ports for Europe and the Pacific, and with equipment shortages and a War Production Board that would not permit new passenger cars, the Pullman Company built 2,400 troop sleepers for the Defense Plant Corporation between 1943 and 1945. Used in regular passenger consists and in solid troop trains until the last soldiers returned, these surplus cars were sold to railroads after 1947 and rebuilt for many other uses. Pullman 8300, built in June 1943 as the first car of the second and smallest of three orders, was a transitional design with 30 bunks arranged in 10 banks three high, including one bunk for a Pullman porter; the middle and lower bunks converted to daytime seating, and the car had four wash basins, two restrooms, weapons racks, and space for foot lockers. Though fitted with an unusual high-speed truck intended for speeds above 100 miles per hour but prone to spontaneous disassembly at speed, it was essentially a freight car with windows and was built at Pullman's freight car plant in Chicago. After the war, car 8300 went to the Alaska Railroad for use as a maintenance-of-way bunk car and survives as a representative of a distinctive car type that provided crucial military service on many railroads, including the Western Pacific.