On January 5, 1918, the line was extended north to Times Square–42nd Street and south to Rector Street. Express service via the line began, with Sea Beach and West End trains that had been running local becoming expresses. The opening of this portion of the line provided additional transit service to Times Square, with a new connection to Brooklyn. Local service henceforth ran between Times Square and Rector Street. Service was extended one station to Whitehall Street–South Ferry on September 20, 1918.