A single extra pulse echo was recorded during the last ultrasonic inspection of the rail, nine months before the derailment, in the vicinity of the failure. An examination with handheld ultrasonic testing equipment at the time concluded there was no sizable defect in the rail, even though the evidence suggests that the fatigue cracks existed (to some degree) at the time.
Safety Recommendation
The Australian Transport Safety Bureau recommends that the ARTC take action to address this safety issue.