railroad accidents

Howard Street Tunnel Derailment


railroad accidentsOn July 18, 2001 a CSX freight train transporting hazardous material derailed in the Howard Street Tunnel in Baltimore, Maryland. One tank car carrying tripropylene was punctured and released its contents, resulting in a fire in the tunnel lasting several days. The result was the evacuation of the downtown Baltimore area and millions of dollars of property damage and business interruption.

James Loumiet and JRLA were hired by the City of Baltimore to lead their multidisciplinary team of experts and investigators to determine the cause and point of derailment and to reconstruct the sequence of events leading up to the derailment. Among the investigation team was three other members of RailroadExperts.com: Richard Beall (train handling), Tom Johnson (metallurgy), and Dennis Percy (track engineering).

railroad accidents

The team inspected the tunnel and the involved rail and railcars. Because major sections of rail had been broken during the derailment and removed from the tunnel, the team conducted a rail rebuild at a nearby facility where the rail sections were matched with corresponding sections and laid out on the ground in sequential order. Numerous wheel marks were found on the rail sections, helping to indicate the point of derailment.

Mr. Loumiet also analyzed event recorder data from the locomotives and ran computer simulations of the train�s expected dynamic performance through the tunnel. By comparing the expected train dynamic performance shown by the simulations (black curve in graph below) to the actual performance shown on the event recorder data (red and blue curves in graph below), Mr. Loumiet was able to identify the location in the tunnel where actual performance deviated from expected performance, indicating the location where the train had derailed and was on the ground.

railroad accidents

Based on all the evidence accumulated by the City�s investigative team, it was determined that the train had derailed at a 48-inch open culvert running under the track and located about � mile into the tunnel. The culvert runs transverse to the tunnel and is part of the City�s storm drain system.

railroad accidentsThe top half and sides of the culvert were cut open in the tunnel by CSX in 1985 to lower the track bed to increase vertical clearance in the tunnel. A 1�-inch steel plate was placed over the cut to support the track structure, with two other plates placed over the vertical portions of the cut. However, the plates and masonry were never sealed so that water from the culvert regularly overflowed into the tunnel. The result was that the track at the culvert was unstable. When car 46 of the train, a box car loaded with paper, reached the culvert, the car derailed due to the unstable track conditions at the culvert. Car 47, which was virtually identical to car 46, derailed at the culvert in the same manner as car 46.

The derailment of cars 46 and 47 generated increased resistance to the forward motion of the train as it began rolling through ties and ballast material, causing it to significantly reduce speed. This speed reduction was exhibited on the locomotive event recorder data. The derailed train continued into the tunnel until it separated between cars 45 and 46. Cars 46 through 56 piled up and came to rest. The 3 locomotives and first 45 cars stopped approximately 470 feet in front car 46.

railroad accidentsThe puncture to tank car 52 caused its tripropylene contents to escape and ignite. The fire spread to the contents of several adjacent cars as well. The fire heated the interior of the tunnel so that the tunnel roof expanded and moved upward. This movement placed stresses on a 40-inch water main above the tunnel until it ruptured approximately 3 hours after the derailment. The rupture of the water main resulted in the flooding of the tunnel with water and sand and the loss of millions of gallons of water.