On November 26, 1967, the Chrystie Street Connection opened, which is considered to be the most important expansion project undertaken by the New York City Transit Authority. The new connection consisted of a pair of double-track tunnels connecting the IND Sixth Avenue Line south of the Broadway–Lafayette Street station with the Williamsburg Bridge and the Manhattan Bridge north tracks. The Broadway Line had previously been connected to the north tracks of the Manhattan Bridge. As part of the project, the Broadway Line was connected to the south tracks, which had been previously used by trains from the BMT Nassau Street Line. The connection between the south tracks and the Nassau Street Line was severed, and the connection between the Broadway Line and the north tracks was also severed. Many routes, including those on the Broadway Line, changed as a result of the opening of the connection. The RR local was rerouted to Astoria, running 24/7 between Ditmars Boulevard and Bay Ridge–95th Street. To replace it in Queens, a new EE local was created, running between Forest Hills and Whitehall Street during weekdays. The Q, which was the only service via the Brighton Line, was converted to the rush-hour only QB, running express in Manhattan from 57th Street. Most of the trips were moved to the IND Sixth Avenue Line as a relocated D, but a few trips stayed as the QB. QT service was discontinued. Another rush-hours only express service, the NX, was created. It ran from 57th Street to Brighton Beach, following the N route, making express stops along the BMT Sea Beach Line, before going through Coney Island to terminate at Brighton Beach. NX service ended on April 12, 1968 due to low ridership.