Analysis of Derailments by Accident Cause

The risk of train derailment associated with rail transportation is an ongoing concern for the rail industry, government, and the public. Various approaches have been considered or adopted to analyze, manage, and reduce risk. Upgrading track quality has been identified as one possible strategy for preventing derailment. The quality of freight railroad track is commonly divided into five principal classes by FRA on the basis of track structure, track geometry, and inspection frequency and method. The higher the track class, the more stringent are the track safety standards and thus a higher maximum train speed is allowed. Upgrading track class is likely to prevent certain track-related derailments; however, this upgrade may also increase the risk of certain types of equipment failure that are more likely to occur at higher speeds. Consequently, more sophisticated approaches need to be developed to examine the interactions among accident causes that may be differently affected by upgrades to track infrastructure. This paper analyzes several critical parameters for predicting train derailment risk by using derailment statistics from the FRA accident database and related literature. A general method was developed to assess derailment risk by accident cause and FRA track class. The safety benefits of track class upgrade in reducing the risks from certain accident causes were quantitatively evaluated. The model can be extended by incorporating additional risk factors to more accurately assess the effectiveness of various derailment prevention efforts for reducing transportation risk.