The conversion was done in order to create a fleet of elevated cars with automatic door controls capable of operating on the BMT Fulton Street Line, whose station platforms had been redone to accommodate 10-foot (3.05 m)-wide equipment instead of the standard 8-foot-9-inch (2.67 m)-wide elevated cars.

The 2 prototypes of the C-type units, created in 1923, presented a fairly neat appearance.

However, the 25 production units created in 1925, with their varying roof heights, floor extensions to reach the platforms, and roof extensions to contain the hangers for the sliding doors presented such an ungainly appearance that they have been popularly characterized as the ugliest equipment ever to run on the New York City subway system.

The cars spent almost their entire lives on the Fulton St. Line, except at the very beginning when they were first tested on the Franklin Ave.

In 1953 and 1954, several units were used on the rush hour West End and Culver Coney Island extension shuttles until December 1953, when through subway service on the West End Line was finally established, and October 1954, when Culver Line service below Ditmas Ave. was taken over by the IND Division.