The KuMoHa 12 was a class of electric multiple unitrailroad cars formerly used by the Japanese National Railways. These are EMU power cars of length with a driver's cab at each end, three passenger doors on each side, and lengthwise bench-type passenger seating. The cars themselves were built in the later 1920s and 1930s for JNR's predecessor, the Japanese Government Railways, but the class, originally named MoHa 12, was established on 1 June 1953 by a JNR revision of its rolling stock classification regulations. In June 1959, a new JNR classification revision assigned the code to all cab-equipped power cars, giving the KuMoHa 12 class its present name. When the MoHa 12 class was formed in 1953, it consisted of 13 cars of the old JGR dual-cab class. Over time, additional cars were added by remodeling related old JGR classes, for an eventual total of 33 cars.
The various KuMoHa 12 cars have the following origins:
12000–12003 - Built in 1933 as dual-cab MoHa 34 cars.
12010–12018 - Built in 1929-1930 as single-cab cars, then remodeled in 1950-1951 with dual cabs as MoHa 34 cars.
12019–12027 - Built in 1929-1931 as single-cab MoHa 31 cars and reclassified in 1953 as series 200. Remodeled in 1958 as dual-cab MoHa 12 cars.
12030–12032 - Built in 1939-1941 as single-cab cars and reclassified in 1953 as MoHa 11 series 400. Remodeled in 1958 as dual-cab MoHa 12 cars.
12040 - Built in 1926 as a single-cab car and reclassified in 1953 as a MoHa 11 series 100. Remodeled in 1960 as a dual-cab KuMoHa 12 car.
12041 - Built in 1927 as a single-cab MoHa 30, remodeled in 1953 as a cabless, and remodeled again in 1964 as tractor car 22112. Converted in 1987 to a KuMoHa 12 for special-event passenger service by JR Central on the Iida Line. This car has been exhibited at the SCMaglev and Railway Park since March 2011.
12050–12055 - Built in 1929-1931 as single-cab MoHa 31 cars and reclassified in 1953 as MoHa 11 series 200. Remodeled in 1959 as dual-cab KuMoHa 12 cars. Later operated byJR East on the Tsurumi Line. The last car was withdrawn in 1996.
