As the IRT (Interborough Rapid Transit) subway expanded in New York City, the need for additional equipment prompted the ordering of 600 low voltage type motor cars. One hundred of these cars came from Pullman in 1916 and 1917, while the remaining 500 were purchased from American Car and Foundry in 1924. An additional 510 non-powered trailer cars entered service between 1916 and 1922. Typical of subway equipment of their day, the steel-sided cars featured rattan seating and rather dim overhead lighting.