The Brooklyn–Manhattan Transit Corporation numbered its services in 1924, Template:Citation needed and the Canarsie and Jamaica services became 14 and 15. As part of the Dual Contracts, an extension from Cypress Hills east to Jamaica was completed on July 3, 1918, a third track was added west of East New York, and express trains began running on it in 1922. The second major service on the Broadway Elevated ran between Canarsie and Williamsburg via the BMT Canarsie Line, started on July 30, 1906, when the Broadway and Canarsie tracks were connected at East New York. This second service later became the 12, and was eliminated on October 13, 1950, with the abandonment of the Lexington Avenue Elevated. It was then a two-track line, with a single local service between the two ends, and a second east of Gates Avenue, where the Lexington Avenue Elevated merged.

The Jamaica Line – then known as the Broadway Elevated – was one of the original elevated lines in Brooklyn, completed in 1893 from Cypress Hills west to Broadway Ferry in Williamsburg. History Before the Chrystie Street Connection 1.1 Before the Chrystie Street Connection.

The current skip-stop pattern was implemented in 1988. The current J/Z descends from several routes, including the JJ/15 between Lower Manhattan and 168th Street in Queens the KK between 57th Street/Sixth Avenue in Midtown Manhattan and 168th Street in Queens the QJ between 168th Street in Queens and Brighton Beach in Brooklyn and the 14 between Lower Manhattan and Canarsie–Rockaway Parkway in Brooklyn. At all other times, only the J operates, serving every station on its entire route. In addition during rush hours and middays in the peak direction, they run express in Brooklyn between Myrtle Avenue-Broadway and Marcy Avenue, bypassing three stations. When the Z operates, the two services form a skip-stop pair between Sutphin Boulevard–JFK and Myrtle Avenue-Broadway. The J operates at all times while the Z, operating as its rush-hour variant, runs with six trips in each peak direction on weekdays both services run through the entirety of the BMT Archer Avenue and Jamaica lines, via the Williamsburg Bridge, and the Nassau Street Line between Jamaica Center–Parsons/Archer in Jamaica, Queens, and Broad Street in Lower Manhattan. Their route emblems, or 'bullets', are colored Template:NYCS const since they use the BMT Nassau Street Line in Lower Manhattan. The J Nassau Street Local and Z Nassau Street Express are two rapid transit services in the B Division of the New York City Subway. Template:Short description Template:Use mdy dates Template:Infobox NYCS service

J line train stops