Pearce Alberta - In its Investigation Report R14C0114 released today, the Transportation Safety Board of Canada (TSB) determined that a Canadian Pacific Railway (CP) train derailed on the Crowsnest Subdivision due to a broken rail near Pearce, Alberta.
 
There were no injuries.
 
On 6 Nov 2014 an eastbound CP train derailed 17 empty covered hopper cars at the tail end of the train on the Crowsnest Subdivision near Pearce, Alberta.
 
The cars derailed in two groups, with the last 10 cars derailing near an adjacent storage track switch, damaging 2 other cars on the storage track.
 
Approximately 600 feet of the main track and the storage track were destroyed, and approximately 1,000 feet of track was damaged between the 2 groups of derailed cars.
 
The investigation determined that the train derailed due to a broken rail near a rail joint.
 
The rail had likely been broken by the preceding westbound train due to a transverse detail defect that had not been detected during ultrasonic testing in September 2014.
 
The defect was not detected likely due to:  the poor rail surface condition was masking the defect, the defect was initially too small to be detected, or the defect developed rapidly to the point of failure between the last ultrasonic test and the date of the derailment.
 
Poor rail surface conditions are known to allow defects to escape detection by ultrasonic testing.
 
Since 2005, the TSB has investigated 7 other occurrences involving rail breaks due to undetected internal defects which were either the primary cause or contributing factor to a derailment.
 
If rail surface defects are not removed by regular rail grinding programs, there is a risk of increased broken rail derailments, as ultrasonic signals may not detect the development and growth of internal rail defects.
 
The Crowsnest Subdivision is made up of a mixture of newer continuously welded rail on curves and older jointed rail in tangents that have been in service for up to 50 years.
 
If fatigued rail remains in service, whether or not it has reached its wear limits, there is an increased risk of service fatigue failures and derailments.
 
Anonymous Author.