As the early 1960s progressed, the East Side experienced an increase in development, and the Lexington Avenue Line became overcrowded. In 1962, construction began on a connection between the Manhattan and Williamsburg Bridges and the Sixth Avenue Line. This segment, the Chrystie Street Connection, was first proposed in the 1947 plan as the southern end of the Second Avenue line, which would feed into the two bridges. When opened in November 1967, the connection included the new Grand Street station on the Sixth Avenue Line (another station, 57th Street, opened in July 1968), and introduced the most significant service changes ever carried out in the subway's history. Grand Street, located under Chrystie Street (the southern end of Second Avenue) was designed to include cross-platform transfers between the Sixth Avenue and Second Avenue Lines.