was suspended from 10:20 a.m. to 12:48 p.m. Immediately after the attacks and more so after the collapses of the Twin Towers, many trains running in Lower Manhattan lost power and had to be evacuated through the tunnels. Some trains had power but the signals did not, requiring special operating procedures to ensure safety. The IRT Broadway–Seventh Avenue Line, which ran below the World Trade Center between Chambers Street and Rector Street, was the most crippled. This section of the tunnel, including Cortlandt Street station (located directly underneath the World Trade Center), was badly damaged, and had to be rebuilt. Service was immediately suspended south of Chambers Street and then cut back to 14th Street. There was also subsequent flooding on the line south of 34th Street–Penn Station. After the flood was cleaned up, express service was able to resume on September 17 with trains running between Van Cortlandt Park–242nd Street and 14th Street, making local stops north of and express stops south of 96th Street, while and trains made all stops in Manhattan (but bypassed all stations between Canal Street and Fulton Street until October 1). 1/9 skip-stop service was suspended. After a few switching delays at 96th Street, service was changed on September 19. The train resumed local service in Manhattan, but was extended to New Lots Avenue in Brooklyn (switching onto the express tracks at Chambers Street) to replace the 3, which now terminated at 14th Street as an express. The train continued to make local stops in Manhattan and service between Chambers Street and South Ferry as well as skip-stop service remained suspended. Normal service on all four trains was restored September 15, 2002, but Cortlandt Street remained closed until September 8, 2018. Service on the BMT Broadway Line was also disrupted because the tracks from the Montague Street Tunnel run adjacent to the World Trade Center and there were concerns that train movements could cause unsafe settling of the debris pile. Cortlandt Street station, which sits under Church Street, sustained significant damage in the collapse of the towers. It was closed until September 15, 2002 for removal of debris, structural repairs, and restoration of the track beds, which had suffered flood damage in the aftermath of the collapse. Starting September 17, 2001, and service was suspended and respectively replaced by the (which was extended to Coney Island–Stillwell Avenue via the BMT Montague Street Tunnel, BMT