Calgary Alberta - The Transportation Safety Board (TSB) has concluded an over stressed switch was behind a train derailment at the Alyth Yard in southeast Calgary in 2013.
 
The Canadian Pacific (CP) Railway train was leaving the Calgary yard for Red Deer on 11 Sep 2013 when the incident occurred.
 
About 140 homes in the surrounding neighbourhood of Inglewood were briefly evacuated.
 
In Railway Investigation Report R13C0087 released Wednesday, the TSB determined the train derailed when a wheel flange struck and climbed a switch point and then fell between the switch point and the rail.
 
Seven tank cars loaded with a condensate commonly used to dilute bitumen derailed, prompting concern about public safety.
 
There were no injuries and no product leaked out.
 
The TSB says CP has made improvements to the track infrastructure, including removing the switch points involved in this occurrence, upgrading the rails, and installing a new turnout.
 
The report is calling for railway companies to review route planning and perform risk assessments.
 
It also says it wants companies to use more "robust" tank cars when shipping flammable liquids.

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