II. The Safety Record of Railroad Bridges
During the past five decades, not one fatality has been caused by the structural failure of a railroad bridge. Train accidents caused by the structural failure of railroad bridges have been extremely rare. Although the average construction date of railroad bridges predates most highway bridges by several decades, the older railroad bridges were designed to carry heavy steam locomotives. Design factors were generally conservative, and the bridges' functional designs permit repairs and reinforcements when necessary to maintain their viability. Railroad bridges are most often privately, rather than publicly, owned. Their owners seem to recognize the economic consequences of neglecting important maintenance. Private ownership enables the railroads to control the loads that operate over their bridges. Cars and locomotives exceeding the nominal capacity of a bridge are not operated without permission from the responsible bridge engineers, and then only under restrictions and conditions that protect the integrity of the bridge. Many railroad bridges display superficial signs of deterioration but still retain the capacity to safely carry their loads. Corrosion on a bridge is not a safety issue unless a critical area sees significant loss of material. Routine inspections are prescribed to detect this condition, but determination of its effect requires a detailed inspection and analysis of the bridge. In general, timber bridges continue to function safely, and masonry structures built as early as the 1830's remain functional and safe for their traffic. Of the few train accidents that involved bridges, most have not been caused by structural failure. FRA accident records for 1982 through 1993 show 15 train accidents that were caused by bridge structural failures, including three that involved improper repair procedures. These accidents caused no reportable injuries and a reported $856,046 damage to railroad facilities, cars and locomotives. During the same period, 29 train accidents on or near bridges were caused by track conditions on the bridge or its approaches. These accidents caused no reportable injuries, and a reported $4,596,733 damage to railroad facilities, cars and locomotives. The same time period saw 19 train accidents on bridges caused by external damage to the bridge, including three fires, 11 floods or washouts, four bridges struck by motor vehicles, and one bridge struck by a marine vessel. The accident at Mobile, Alabama on September 22, 1993 alone caused 47 fatalities, 102 non-fatal injuries, and over $10,000,000 in property damage. The losses from these 19 accidents totaled 47 fatalities, 124 non-fatal injuries, and $22,150,865 damage to railroad facilities, cars and locomotives. The severity of a train accident is usually compounded when a bridge is involved, regardless of the cause of the accident. FRA must retain its capability to deal effectively with any safety problems involving the structural integrity of railroad bridges. At the same time, FRA must assure that private and public resources are not diverted unnecessarily from other programs that are also critical to railroad safety. At one extreme, FRA could respond to bridge issues only when accidents occur or when someone contacts the agency about particular concerns. However, such a reactive policy would inhibit FRA's ability to detect impending problems with railroad bridges. At the other extreme, FRA could regulate all aspects of railroad bridge management, including inspection, rating, construction and maintenance. The expense to the railroad industry of such a policy is not justified by the findings of the safety survey. Because the industry has no apparent systemic bridge safety problem, FRA chooses to adopt a policy, rather than issue regulations, to carry out its responsibility of protecting bridge safety. The policy includes IV. Bridge Safety Policy
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