From the 1990s until mid-2001, "World's Fair" cars 9478–9523 usually ran on the train based at Westchester Yard in the Bronx. Previously, some Westinghouse-equipped cars had been assigned to the and trains in the 1970s. The "Main Line" cars usually ran on the ' from 1984 to 1988, and were transferred to the ' from 1988 to 2001, when they were returned to the 7. During this time, some cars also provided occasional service on the 4 route, which occasionally uses equipment borrowed from the 6.