TSB report says laterally shifting track derailed one train
(Canadian OH&S News) — A new report from the Transportation Safety Board of Canada (TSB) has concluded that the conditions of the track caused the derailment of a freight train near Faust, Alta. on June 11, 2014. The TSB also noted that track failure in the area had also led to five other derailments during the spring and summer of 2014.
The incident on which the report focused had occurred as a Canadian National (CN) train was heading eastbound from McLennan to Smith. At about 3:30 p.m. local time, as the train went through the Slave Lake Subdivision, the last 20 cars derailed, including 17 Class 111 tank cars contained diesel-fuel residue. There were no injuries or fatalities in the derailment, and none of the product was released, but the incident damaged more than 350 metres of track.
A subsequent investigation by the TSB determined that irregular and insufficient rail anchoring, unstable subgrade and high stress buildup had caused the track to shift laterally under the moving train. Investigators also speculated that the track stress had accumulated due to repeated brake exposure from eastbound trains on a descending grade. “No defects on the locomotive or cars were identified,” the report read.
The report, which was published last Dec. 22, identified three other derailments that had occurred in the Slave Lake Subdivision in 2014 — on May 8, June 12 and Sept. 16 — as well as two that had happened in the Westlock Subdivision over the same period. These areas had been accommodating a significant increase in rail traffic since the Lac-Mégantic disaster of July 2013, after which these Subdivisions were identified as recommended “Key Routes”.
“The condition of the track could not handle the traffic levels that had increased significantly on this corridor since 2013, in advance of the recommended infrastructure improvements,” the TSB stated in the report. “If the impact of increased traffic levels on track infrastructure is not adequately assessed or mitigated, the risk of derailments will increase.”
In the wake of this and other derailments, the TSB issued a rail safety advisory about possible infrastructure issues in the Slave Lake and Westlock Subdivisions, as well as a letter to CN regarding potential risks in these areas, both on Sept. 19, 2014. In response, CN performed a risk assessment of the Slave Lake Subdivision area and increased ultrasonic and geometry testing programs there.
“As this occurrence demonstrates, the increase in the transportation of flammable liquids – such as crude oil – by rail across North America has created emerging risks that need to be effectively mitigated,” said the report.
“The TSB has called on railway companies to conduct route planning and analysis, and perform risk assessments, to ensure that risk-control measures are effective.”