a Mean Distance Between Failure (MDBF) rate of 194,150 miles, despite being 35 years old at the time. While in decent shape mechanically, rust holes and car body corrosion were beginning to form in the sides of most of the cars. From December 1987 until July 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 late 1960s–early 1980s. The "Main Line" cars usually ran on the from February 1984 to December 1987, and was transferred to the from December 1987 to June 2001, when they were returned to the . Retirement In 1996, the New York City Transit Authority announced their plans to phase out the Redbirds with the R142 and R142A fleets. From February 2001 to July 2001 as R142As enter service on the , the "Main Line" R36s and "World's Fair" cars 9478–9523 were transferred over to the . While the Redbirds on the IRT Main Line were retired starting in early 2001, the service was still provided by R33S cars and R36s. In January 2002, a set of R62As arrived from the IRT mainline. As more R142s and R142As were delivered, R62As were gradually transferred from the and to the , in turn replacing the R33S cars and R36s. The last "Main Line" R36 pair, 9542–9543, made its final trip on the on May 16, 2003. The last train of "World's Fair" R36s, consisting of pairs 9564–9565, 9616–9617, 9582–9583, 9584–9585, and 9586–9587 finally ran along the on November 3, 2003, with R33S car 9309, marking not only the end of the Redbird cars, but also the end of non-stainless steel cars on the subway. Most of the Redbirds (1,294) were stripped and then submerged off the coast of Delaware, New Jersey, South Carolina, Georgia, and Virginia as an artificial barrier and diving reefs, by Weeks Marine. Several R36 cars were saved for various purposes throughout the New York City Subway system. The full list includes: "Main Line" pair 9542–9543 – preserved by the New York Transit Museum in Brooklyn since 2004. This pair is currently stored at the 207th Street Yard, awaiting restoration. "World's Fair" pair 9586–9587 – also preserved by the New York Transit Museum in Brooklyn. These cars were stored for many years until being moved to the Concourse Yard in summer 2013. In