three to four rail cars. Impact on Baltimore downtown region Thousands of Baltimore workers were forced to leave their jobs and unable to come back for several days until the city could assure that there was no further danger from either the fire or the water main flooding. The crash also impacted MARC passenger train service for several days; bus routes were set up by the city to ferry passengers to and from the BWI Amtrak/MARC station as an alternate route. MARC service was restored on July 23, 2001. Most of the roads around Howard Street, including I-395 spur into Baltimore, experienced extremely heavy congestion due to street closures around the intersection of Howard and Lombard Streets, where the actual water main break occurred. By July 24, 2001, all but the blocks immediately surrounding the water main break were reopened to automotive traffic. Three weeks later, manhole covers flew into the air as underground explosions along West Pratt Street occurred due to residual explosive chemicals from the fire in the sewers. Smoke from the incident and flooding from the broken water main caused three Baltimore Orioles baseball home games to be canceled that summer, as Oriole Park at Camden Yards was directly in the danger zone caused by the fire. Impact on East Coast rail traffic The Howard Street Tunnel is on the only direct rail link on the CSX rail line from Philadelphia to Washington, D.C. The only other direct rail link is the Amtrak Northeast Corridor, a passenger line with only limited freight operations performed by Norfolk Southern Railway. According to the U.S. Department of Transportation (DOT) report on the incident, officials had long known that the possibility existed for a fire or other disaster to cause a significant problem in the Howard Street Tunnel. An article published in the Baltimore Sun on July 19, 2001, contains a 1985 quote from an unidentified federal transportation safety official who observed, "... the problem would be getting in there to fight the fire... If you had an explosion, fire would shoot out of both ends like a bazooka." However, freight traffic on the line had been increasing for years as CSX and Conrail diverted traffic away from Amtrak lines to avoid Amtrak/Conrail crashes like the one in Chase, Maryland in 1987. Estimates from railway publications put the freight traffic through the Howard Street Tunnel at 28 to 32 trains per