Retirement and after-life service

In 1996, New York City Transit Authority announced their plan to phase out the Redbirds with the R142 and R142A fleets. While the Redbirds on the IRT Main Line were beginning to be retired starting in early 2001, the 7 service was still provided by R33S and R36 cars. 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 3 and 6 to the 7, in turn replacing R33S/R36 trains. The last car remaining R33S, 9309, made its final trip on November 3, 2003, on the 7 service with ten R36 cars, marking the end of the Redbirds and non-stainless steel cars in the subway.

Most R33S cars were converted to work motors in the early 2000s, and handle such tasks as providing traction for B-Division rail adhesion cars and refuse trains. The number "1" was placed before the former number (i.e. car 9345 became 19345) of some cars. The work cars are based out of various yards around the system and handle such tasks as providing traction for A-Division rail adhesion cars and refuse trains, and hauling cars during car moves between different subway yards. The cars that were not converted were 9306 and 9327, which were preserved as heritage cars after their retirement from revenue service, and 9321, which was stripped and sunken as an artificial reef in 2001.

Recently, the remaining R33S cars have been decommissioned as they experience structural or mechanical issues. Car 9339 was retired, stripped, and then sunken as an artificial reef in 2010 after it suffered fire damage that year. A handful of cars were replaced by reassigned R32 cars, stripped of parts to keep other IRT SMEE cars running, and then scrapped in 2013. Four cars were sidelined in 2017, after which they were sent into preservation. Currently, another handful of cars are being replaced by reassigned R42 cars.

Six cars have been preserved:

• Cars 9306, 9307, 9308, 9310, and 9343 have been preserved by the New York Transit Museum in Brooklyn. 9306, part of the museum since July 1976, is the only R33S car to not be rebuilt, and thus bears the World's Fair paint scheme and original interior configuration. 9307, 9308, 9310, and 9343 were previously used as work motors based out of Corona Yard, before being retired in 2017. Cars 9307 and 9308 are also painted in the World's Fair scheme, and car 9310 is painted in the "Redbird" scheme; it is unknown what scheme 9343 will be repainted to. All cars except 9343 are fully operational and run periodically on museum-sponsored "Nostalgia Trains", specifically on the Train of Many Colors.
• Car 9327 is preserved at the Seashore Trolley Museum in Kennebunkport, Maine, painted in the Subway Series livery. The car was temporarily displayed at the New York Transit Museum and was used on a fan trip in May 2005 before being sent to Kennebunkport. It is fully operational, though modified with trolley poles, and makes occasional runs around the museum, often coupled to R22 car 7371.