The Transportation Safety Board of Canada (TSB) pointed out on Feb 16:
Undetected fatigue cracks in the joint bars
Repetitive impacts from train wheels
Joint bar failures are the cause of CN crude oil unit train derailment near Gogama, Ontario in February 2015.
CDR High Strength (Charpy) Bar
Taking advice from one professionals in rail industry in 2012, CDR started to develop High Strength (Charpy) Bar especially for requirement of North America and High & Cold Region.
With High mechanical properties, it can better ensure rail safety.