Planning for the 63rd Street Line's $645 million connection from the 21st Street–Queensbridge station to the IND Queens Boulevard Line in Queens began in December 1990, and construction began on September 22, 1994. The Connector came into regular use on December 16, 2001. A new Sixth Avenue local service, the V, was introduced operating local via Sixth Avenue and terminating in the center tracks of the Sixth Avenue Line's Second Avenue station. The V ran local on the Queens Boulevard Line, and it only operated during weekdays. At this time, the F, which ran express along the Queens Boulevard Line, was rerouted to operate via the 57th Street station and the 63rd Street line north of the 47th–50th Streets–Rockefeller Center station, rather than via the 53rd Street tunnel. Both the 63rd Street and the 53rd Street lines merge into the Queens Boulevard Line in Queens. On June 28, 2010, the V was replaced by the M, which began using the Chrystie Street Connection to the Williamsburg Bridge. Regular M trains make all former V stops except for Second Avenue.