The T Second Avenue Local is a prospective rapid transit service in the B Division of the New York City Subway.

[4] The Saturday morning rush hour local service to Chambers Street, on June 24, 1950, was discontinued.

On October 24, 1957, late night service was replaced by locals to Chambers Street, running via the tunnel in both directions, and terminating at Coney Island–Stillwell Avenue.

On January 1, 1961, rush hour T expresses began running to Astoria–Ditmars Boulevard in along the BMT Astoria Line in Queens, and until April 2, 1962 so did Saturday service.

TT local service on January 1 began running between Bay Parkway and Chambers Street.

The new color scheme for subway routes introduced that day included a blue TT bullet.

From April 26, 1986 to December 11, 1988, the northern tracks of the Manhattan Bridge, leading to the Sixth Avenue Line, closed for repairs, akin to the conditions of the subway prior to the opening of the Chrystie Street Connection.

[13] This lasted until February 22, 2004, when, following the completion of repairs to the Manhattan Bridge, the D was rerouted over the West End Line, providing full-time service via Sixth Avenue Express, which continues today.

The T was programmed into R44 and R46 side signs as a West End route, with various Broadway, Sixth Avenue and Nassau Street designations.

[4] During planning for the Second Avenue Subway in the early 2000s, the MTA decided to designate the line's future full-length service with the letter T, in part because:[17] The T's route emblem is colored turquoise (hex triplet #00ADD0, which could also be considered robin's egg blue or teal) because the color had also been used for the JFK Express in the past.

[20][21] After Phase 4 opens, T service will run the full length of the line, from Harlem–125th Street to Hanover Square.