SS (New York City Subway service)

Three services in the New York City Subway are designated as a dark slate gray S (shuttle) service. These services operate as full-time shuttles. In addition, three services run as shuttles during late night hours but retain their regular service designations.

Other routes have in the past been designated S or SS; the label has also been used for temporary shuttles due to construction. Before June 1979, all shuttles had the label SS; the designation S was reserved for "special"' services, including IND trains to Aqueduct Racetrack. The SS label was first applied in 1967, when all services were labeled due to the completion of the Chrystie Street Connection.

Former uses of the S or SS designation are as follows:

Some shuttle routes also used the H or HH designation, which were the last to be assigned to the Independent Subway System. Former uses include the Court Street Shuttle from 1936 to 1946 and Rockaway Park Shuttle until 1993, when that route's label was changed to a blue S. A temporary shuttle opened in November 2012 after Hurricane Sandy destroyed track connecting the Rockaways to the rest of the system used the H designation.

When the Transit Authority began assigning labels to all services, the Third Avenue Elevated was designated as 8 because it was deemed too long to be considered a "shuttle". However, trains on this line showed SHUTTLE on their rollsigns instead of "8". The service was discontinued in 1973.

The Lenox Terminal Shuttle (also Lenox Shuttle and Lenox Avenue Shuttle) ran between 148th Street and 135th Street when the 3 did not run. Prior to May 13, 1968, it was called the 145th Street Shuttle, running only to 145th Street, and only from 9:00 pm to 1:00 am. It was in place by 1918, but may have been started in 1905 when the IRT White Plains Road Line opened to the IRT Lenox Avenue Line.

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