The Australian Transport Safety Bureau (ATSB) has blamed degraded tracks for a derailment in Victoria.

A Pacific National train rolled over after leaving the tracks near Ouyen last year.

The national transport safety authority’s investigations have shown degraded condition of rail joints was not noticed during track inspections by V/Line authorities prior to the crash.

Their report shows fatigue led to cracking, which may have contributed to rail joint failures.

ATSB said the last checks were more than two years before the derailment, and conducted visually from the cab of a moving vehicle. Inspectors did not pick up on deteriorating mechanical connections at the time.

The last walking track inspection had been conducted even earlier, and ATSB said it saw no records for other planned inspections after that date.

V/Line says it has improved its maintenance protocols to boost the detection of track defects in particular, and the ATSB says it is satisfied this action will address the issues.