Temporal Trends in Freight Train Derailment Rates and Severity under Changing Railway Operations

Abstract Ensuring the safe, reliable, and efficient operation of the freight rail network is vital to the economy of the United States. Freight train derailments may negatively impact infrastructure, equipment, operations, surrounding populations, and the environment. While the long-term trend in mainline freight train derailment rates exhibits a steep decline over the past several decades, the derailment rate may no longer be declining as freight railroads implement new operating practices. To investigate how derailment rates for various causes have changed with recent changes in operations by the four largest US freight railroads, mainline train derailment and freight rail traffic data from the last six available years (2018–2023) are subject to statistical analysis to compare normalized derailment rate (frequency) and severity with that of the previous six years (2012–2017). To advance upon previous study of temporal trends in train-mile derailment rates that are now outdated, these two analysis periods distinguish recent years with “precision scheduled railroad” operating practices emphasizing, among other things, increased train lengths, from an earlier period of equal duration when freight trains were substantially shorter on average. The study uses a measure of train length as a proxy for overall changes in railroad operations between the two periods and also implements cause-specific normalization by train-miles and car-miles to better control for changes in train size over time. The analysis demonstrates that while train size (number of railcars per train) is correlated with increasing derailment rates for certain causes related to train make-up/handling and human factors, derailment rates for other causes have declined. Derailment severity, measured as the average number of railcars derailed per incident, also appears to be correlated with train size, consistent with the findings of others. Understanding the revealed changes in derailment rate, severity, and causes can help inform and prioritize the deployment of train safety management systems and training for operating personnel, ultimately leading to improved safety and efficient operation of longer freight trains. While the data used have significant limitations, they still provide an accurate assessment of how derailment rates and causes have changed between the periods before and after substantial changes in operations at most/all major US railroads.