Lines and the 63rd Street Lines are each classified as two separate lines due to their structure: both lines are able to serve two divisions (the BMT and the IND) on distinct sections of track. In the list below, lines with colors next to them indicate trunk lines, which determine the colors that are used for services' route bullets and diamonds, as well as shuttle service lines. The opening date refers to the opening of the first section of track for the line. In the "division" column, the current division is followed by the original division in parentheses. Inter-division connections The following list shows the connections between the different divisions of the New York City Subway. Purpose-built These connections can be used by trains in revenue service: 60th Street Tunnel Connection, also known as the 11th Street Cut (Queens) (BMT/IND) ( train) 63rd Street Lines (Manhattan) (BMT/IND) Coney Island–Stillwell Avenue station (BMT/IND) (originally all BMT) ( trains) Chrystie Street Connection (Manhattan) (BMT/IND) via the Manhattan Bridge ( trains) and via the Williamsburg Bridge ( train) This connection is not for revenue service due to the differing widths of the trains: Astoria Line / Flushing Line (Queens) (BMT/IRT) Yards These connections are located within the subway's rail yards and are not intended for revenue service. 207th Street Yard (Manhattan) (IND/IRT); trains from the IND Eighth Avenue Line and IRT Broadway–Seventh Avenue Line Coney Island Complex (Brooklyn) (BMT/IND); trains from the IND Culver Line, BMT Sea Beach Line and BMT West End Line Concourse Yard (Bronx) (IND/IRT); trains from the IND Concourse Line and IRT Jerome Avenue Line Linden Yard (Brooklyn) (BMT/IRT/LIRR); trains from the BMT Canarsie Line and IRT New Lots Line Other BMT West End Line / South Brooklyn Railway (Brooklyn) (BMT/Mainline RR) Unused connections in the same division In some places, there are track connections within the same division that are unused in regular service. Brooklyn At Coney Island–Stillwell Avenue, see above. At Broadway Junction, there is an unused flyover between the BMT Canarsie Line and the BMT Jamaica Line. At Prospect Park, the tracks of the BMT Franklin Avenue Line become the local tracks of the BMT Brighton Line. At DeKalb Avenue, there is an unused connection between the BMT Brighton Line and the BMT Broadway Line via the Montague Tunnel. Manhattan At West Fourth Street–Washington Square, there is an unused connection between the local tracks of the