They were the last entirely LAHT bodied (non-stainless steel) cars built for the New York City Subway.

They were built from unfinished car body shells of the R33 order, and therefore featured sported drop-sash side windows.

[2] On October 22, 1976, Westinghouse "World's Fair" R36s 9504–9523 were moved from the 7 to the 1 and 3 to supplement the "Main Line" cars.

The "World's Fair" R36s were the first cars to be rebuilt in the NYCTA's General Overhaul Program (GOH) in the 1980s.

Others were rebuilt by General Electric in Buffalo, New York, and by Amtrak at its Beech Grove, Indiana, and Wilmington, Delaware shops.

After rebuilding, the R36 cars were repainted in a scheme involving a deep maroon red body, black front bonnets and anti-climbers, and a silver roof prior to returning to service.

Starting in late 1992, R36 cars 9558–9769 underwent another overhaul to improve their reliability that involved some cosmetic improvements, extensive rewiring, and the installment of donor cam control group and braking systems that were salvaged from the retiring R30 cars.

In 1999, the R36 cars were the most reliable in the NYCT fleet, with a Mean Distance Between Failure (MDBF) rate of 194,150 miles, despite being 35 years old at the time.

From December 1987[3] until July 2001,[4][5][6] "World's Fair" cars 9478–9523 usually ran on the 6 train based at Westchester Yard in the Bronx.

In 1996, the New York City Transit Authority announced their plans to phase out the Redbirds with the R142 and R142A fleets.

While the Redbirds on the IRT Main Line were retired starting in early 2001, the 7 service was still provided by R33S cars and R36s.

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.

"World's Fair" pair 9400–9401 was stored at the Corona Yard for preservation; however, the cars were never used and were scrapped on October 7, 2013.

"World's Fair" pair 9564–9565 was set aside and transferred to Coney Island Yard in December 2004; car 9564 was planned to be repurposed into a visitor center at Queens Borough Hall in Kew Gardens, Queens, and the car 9565 was planned to be preserved in a museum in West Babylon, New York.

However, R33 9075 was used at Queens Borough Hall instead of 9564, and 9565 never made it to the proposed museum; the cars were subsequently reefed in 2008.

In addition, the "World's Fair" cars have made cameo roles in various TV shows and movies.