SANDRA M STANWAY
Brooks Bulletin
The Transportation Safety Board of Canada has determined that the cause of the July 2022 derailment in Bassano was deterioration of the track.
“The track buckled under the passage of CP train 301-222 leading to the derailment of 41 cars (of 203 cars) at Mile 97.4 of the Brooks Subdivision near Bassano, Alberta,” Transportation Canada reported in its investigation that was released last week.
The investigation found that the track showed signs of degradation that was consistent with many years of service and high volumes of loaded unit traffic in the vicinity of the derailment.
Video from the 44 mph (71 km) train did not show any indication of a defect in the track when the locomotive passed over Mile 97.4, however, when the mid-train locomotives passed over the same location, “There was noticeable side-to-side sway in the recorded video indicating that a misalignment developed progressively under the train.”
That misalignment continued to develop with each passing car “until it was too large for the 116th car to negotiate.”
Inspectors found that the deteriorated track conditions included contaminated and worn ballast, lifted spikes, rail creep marks, missing or loose anchoring and skewed, worn and plate-cut ties.
“Signs of deterioration had also been evident in track inspection records for more than a year,” states the report. It noted that there had been frequent urgent narrow-gauge conditions which may be indicative of insufficient track securement and elevated compressive forces.”
Maintenance had been done on the track the month prior to the incident and CP was attempting to address track surface conditions.
Urgent alignment defects had been repaired a few days before the derailment.
“The track structure in the vicinity of the derailment was in a deteriorated condition that reduced lateral stability and made the track more susceptible to buckling.”
The temperature rose from 14.9C on July 6 to 31.6C on July 12 was also a factor in the derailment because it subjected the rail line to stress.
“The occurrence train was traversing the area at a time when daytime temperature and consequently the thermal compressive stress (created a condition that made the track vulnerable to a track buckle) from the ambient temperature was at its highest,” states the report.
Following the incident a number of occurrences took place by CP which included track renewal, a vehicle was used to evaluate the condition of the track, changes to training for supervisors of track inspections and changes to speed and track temperature.
