The Broadway - Brooklyn shortline was a combination of the Jamaica el and Canarsie line . It went from Broadway Ferry (Williamsburg terminal) to Canarsie Pier. In May of 1906, the Brooklyn Rapid transit purchased the Canarsie Railroad and leased it to the Union Elevated railroad company. They elevated the line from New Lots Ave to Atlantic Ave and relocated part of the line adjacent to the LIRR Bay Ridge Branch. As of July 28, 1906, the surface route was electrified with trolly wire and the elevated portion electrified with third rails west of E 105th street. The Broadway el continued going to the now vanished Williamsburg terminus (Broadway Ferry) 9/4/1885 - 1917, but also extended over the Williamsburg bridge on September 16, 1908 to Essex terminal. This allowed the Broadway el and Broadway Brooklyn shortlines into Manhattan for the first time. Later, it was extended to Chambers by 8/14/1913. In 1913, a section of the Canarsie line was eliminated from Rockaway Pkway to Canarsie shore. This section of track became a trolly service until the 1940s.

The BRT was reorganized as the Brooklyn Manhattan transit (BMT) in 1923. In 1924, the BMT started labeling its trains with numbers. This service was known as the BMT #14 train. On July 14, 1928, the NEWER 14th street section of the Canarsie line was connected to a new elevated station built over an existing elevated station called Broadway Junction (Eastern Parkway). This new platform was extended south to the 'rebuilt in 1916' six track Atlantic Ave station to Canarsie Landing. This Atlantic Ave station served the Canarsie, Fulton el, and Broadway els. (The eastern-most platform of this station is a remnant of the Fulton street el NOW served by the train since 2003.) Years later, the line went beyond Essex street in Manhattan and was extended to Fulton street - Nassau street on 5/30/1931. The older part of the Canarsie line was renamed the Broadway - Brooklyn providing weekday local service over the Broadway el west of Broadway Junction (Eastern Parkway).

The BMT #14 train was renamed the train 11/27/1967 to 6/30/1968 from Rockaway Parkway on the Canarsie line to Broad street, Manhattan. A secondary service was created as well from 168th street on the Jamaica el to Broad street. Due to severed track connections between the Jamaica el and Canarsie line at Atlantic Ave, the services were phased out and the new service was implemented 7/1/1968 between 168th street Jamaica and 57th street/ Sixth Ave Manhattan. On 1/2/1973, the was renamed and was shortened from Eastern Parkway to 57th street/ Sixth Ave 1/2/1973 to 8/27/1976. The Broadway - Brooklyn short line was considered the second major service along the Broadway el (Jamaica el).