High Quality Content by WIKIPEDIA articles! The A Division, also known as the IRT Division, is a division of the New York City Subway, consisting of the lines operated with services designated by numbers (1, 2, 3, 4, 5, 6, and 7) and the 42nd Street Shuttle. These lines and services were operated by the Interborough Rapid Transit Company before the 1940 city takeover. A Division cars are narrower, shorter, and lighter than those of the B Division, measuring 8.6 ft (2.621 m) by 51 ft (15.545 m) .