The N was originally the Brooklyn–Manhattan Transit Corporation's 4 service, running along the BMT Sea Beach Line to the Manhattan Bridge. The 4 used the BMT Nassau Street Line in Lower Manhattan from 1915 to 1917, after which it ran express on the BMT Broadway Line. The 4 became the N in 1961. The N ran local in Queens along the IND Queens Boulevard Line to Forest Hills–71st Avenue from 1976 until 1987, when it switched terminals with the R. From 1986 to 2004, reconstruction on the Manhattan Bridge forced the N to run local on the Broadway Line via the Montague Street Tunnel.