A train derailment in the Columbia River Gorge near Mosier, Oregon resulted in a fire that burned for 14 hours. The Federal Railroad Administration (FRA) preliminary investigation says the June 3rd derailment was caused by a broken lag bolt which allowed the track to spread, resulting in the 16-car derailment. Although there is only one other known instance of a broken lag bolt causing a train derailment, the FRA determined that the bolt had been damaged for some time, and had been inspected within days of the incident, raising questions about the effectiveness of these inspections.
Determining all the causes of a complex issue such as a train derailment can be difficult, but doing so will provide the widest selection of possible solutions. A Cause Map, or visual root cause analysis, addresses all aspects of the issue by developing cause-and-effect relationships for all the causes based on the impacts to an organization’s goals. We can create a Cause Map based on the preliminary investigation. Additional causes and evidence can be added to the map as more detail is known.
The first step in the Cause Mapping process is to determine the impacts to the organization’s goals. While there were no injuries in this case, the massive fire resulting from the derailment posed a significant risk to responders and nearby citizens, an impact to the safety goal. The release of 42,000 gallons of oil (although much of it was burned off in the fire) is an impact to the environmental goal. The customer service goal is impacted by the evacuation of at least 50 homes and the regulatory goal is impacted by the potential for penalties, although the National Transportation Safety Board (NTSB) has said it will not investigate the incident. The state of Oregon has requested a halt on oil traffic, which would be an impact to the schedule goal. The property goal is impacted by the damage to the train cars, and the labor/ time goal is impacted by the response and investigation.
The analysis, which is the second step in the Cause Mapping process, begins with one of the impacted goals and develops cause-and-effect relationships by asking ‘Why’ questions. In this case, the safety goal is impacted by the high potential for injuries. This is caused by the massive fire, which burned for 14 hours. There may be more than one cause resulting in an effect, such as a fire, which is caused by heat, fuel, and oxygen. The oxygen in this case is from the atmosphere. The heat source is unknown but could have been a spark caused by the train derailment. The fire was fueled by the 42,000 gallons of crude released due to damage to train cars, which were transporting crude from the Bakken oil fields, caused by the derailment.
The derailment of 16 cars of the train was caused by the broken lag bolt. Any mechanical failure, such as a break, results from the stress on that object exceeding the strength of the object. In this case, the stress was caused by the weight of the 94-car train. The length of a train carrying crude oil is not limited by federal regulations. The strength of the bolts was reduced due to previous damage, which was not identified prior to the failure. While the track strength is evaluated every 18 months by the Gauge Restraint Measurement System (GRMS), it did not identify the damage. It’s unclear the last time it was performed.
Additionally, although the track is visually inspected twice a week by the railroad, it is done by vehicle, which would have made the damage harder to spot. The FRA does not require walking inspections. Nor does the FRA inspect or review the railroad’s inspections very often – there are less than 100 inspectors for the 140,000 miles of track across the country. There are only 3 in Oregon.
As a result of the derailment, the railroad has committed to replacing the existing bolts with heavy-duty ones, performing GRMS four times a year, enhanced hyrail inspections and visual track inspections three times a week, and performing walking inspections on lag curves monthly.
The FRA is still evaluating actions against the railroad and is again calling for the installation of advanced electronic brakes, or positive train control (PTC). It has also recommended PTC after other incidents, such as the deaths of two railroad workers on April 3 (see our previous blog) and the derailment in Philadelphia last year that killed 8 (see our previous blog).
To view a one-page PDF of the Cause Mapping investigation, click on “Download PDF” above. Or, click here to read the FRA’s preliminary investigation.