lines backed up traffic regionally and nationally because the fiber-optic cable through the tunnel is a major line for the extremely busy Northeast Corridor. The Inner Harbor was closed to boat traffic. A water-main break near the tunnel added to the chaos, causing the collapse of part of a major thoroughfare and power outages. The severed optical fiber cable in the tunnel was a major east coast internet communication link belonging to WorldCom. The break slowed internet service around the US for several hours; water from the water main break caused further damage to the communication lines. According to the DoT report, WorldCom was able to install a fully redundant network bypass around the incident within 36 hours, allowing resumption of east coast and transatlantic internet communications. The aftermath of the fire affected some activities for longer periods. MTA shut down light rail service through the city for over seven weeks, with shuttle buses running between the North Avenue and Patapsco stations, and later between North Avenue and Camden. The intersection at Howard and Lombard streets, one of the busiest in the city, was not re-opened until September 5. See also Summit Tunnel fire a similar incident in the UK involving a freight train carrying petrol derailing and catching fire in a tunnel. List of rail accidents (2000–2009) References External links NTSB report NIST numerical simulation of the fire Effects of Catastrophic Events on Transportation System Management and Operations – DOT report FRA Report To Congress: Baltimore's Railroad Network, Challenges and Alternatives, November 2005 Part 1: Challenges, discussing the history and recent state of Baltimore rail infrastructure. Part 2: Alternatives, discussing possible new tunnel alignments. Railway accidents in 2001 Railway accidents and incidents in Maryland 2001 in Maryland Derailments in the United States Rail crash Accidents and incidents involving CSX Transportation Fires in Maryland Train and rapid transit fires Tunnel fires Chimney effect fires 2001 fires in the United States July 2001 events in the United States