The National Transportation Safety Board investigates major railroad accidents in the United States. It was not only the severity (6 deaths and 126 injuries) but the frequency (5 accidents over 11 months) of recent accidents on a railroad that led to an “in-depth special investigation“. Part of the purpose of the special investigation was to “examine the common elements that were found in each”.
When an organization sees a recurring issue – in this case, multiple accidents requiring investigation from the same railroad, there may be value in not only investigating the incidents separately but also in a common analysis. A root cause analysis that addresses more than one incident is known as a Cumulative Cause Map, and it captures visually much of the same information in a Failure Modes and Effects Analysis, or FMEA.
The information from the individual investigations of each of these accidents can be combined into one analysis, including an outline addressing the problems and impacts to the goals from the incidents as a whole. In this case, the problems addressed include issues on the Metro-North railroad in New York and Connecticut from May 2013 to March 2014. The five incidents during that time period resulted in 4 customer deaths and 126 injuries, 2 employee deaths, and over $23.8 million in property damage.
The analysis of the individual accidents can be combined in a Cumulative Cause Map to intuitively show the cause-and-effect relationships. The customer deaths and injuries, and the property damage, resulted from train derailments and a collision. The train collision resulted from a derailment. In two of the cases, the derailment was due to track damage that had either been missed on inspection or had maintenance deferred. In the third derailment (discussed in a previous blog), the train took a curve at an excessive rate of speed due to fatigue of the engineer. Inadequate track inspections and maintenance, and deferred maintenance were highlighted as recurring safety issues to the railroad.
Both of the employee fatalities resulted from workers being struck by a train while performing track maintenance. In one case, the worker was outside the designated protected area due to an inadequate job safety briefing. In the other, a student removed the block while working unsupervised, allowing a train to travel into the protected area. The NTSB also identified inadequate safety oversight and roadway worker protection procedures as areas needing improvement. While the NTSB already released recommendations with each of the individual investigations, it plans to issue more based on the cumulative investigation addressing all five incidents. View an overview of all 5 incidents by clicking “Download PDF” above.