Investigation launched after train derails near Ōtira Tunnel

A loaded KiwiRail coal train derailed as it was approaching the Ōtira Tunnel yesterday, leaving the Midland Line - which runs between Rolleston and Greymouth - closed with extensive damage.

The Transport Accident Investigation Commission have launched an inquiry into the derailment, which happened at about 10pm Tuesday.

The coal train was heading towards Christchurch when the last wagon derailed.

The train stopped inside the Ōtira Tunnel, with extensive damage to the train and rail infrastructure. There were no injuries to the crew reported.

KiwiRail manager engineering Lynne Morton said it was assessing the extent of the damage and repairs needed.

"We are working to restore the line as quickly and safely as possible."

She said today's TranzAlpine service would only operate as far as Arthur's Pass, and services were likely to be affected for the next few days.

"Affected passengers will be contacted directly and offered rebooking or refund options. Replacement buses will be arranged where possible."

"KiwiRail is also working closely with affected freight customers to manage the disruption."

TAIC chief investigator of accidents Louise Cook said a team of investigators had been appointed to gather evidence.

"Our investigators would typically spend two to three days on site. Their first priority is to gather evidence while it is available. That includes examining and mapping the train and the scene, and speaking with people who witnessed the accident or were involved."

She said the commission's investigators will examine the locomotive, rolling stock and rail infrastructure, secure data and maintenance records, and interview the train crew and other staff of the operator.

Cook said the purpose of TAIC inquiries was to improve transport safety, looking for lessons that could help avoid further accidents.