The Transport Accident Investigation Commission (TAIC) identifies eight safety issues and makes five recommendations in a report published today about the circumstances and causes of an August 2021 passenger train derailment during intense rain near Paekākāriki.

A Transdev Wellington commuter train was under way from Palmerston North to Wellington during forecasted heavy rainfall. It rounded a curve just South of Paekākāriki to encounter the track ahead covered in landslip debris. The debris had washed over the tracks because nearby drains and culverts were overwhelmed by heavy rainfall in the adjacent hills. Emergency braking didn't stop the train and while three of its passenger cars derailed, the whole train remained upright. All on board – 82 passengers, three crew – evacuated safely with no injuries.

TAIC's Chief Investigator of Accidents Naveen Kozhuppakalam says this is the third TAIC report in just over two years that highlights the need for KiwiRail to improve its preparation and responsiveness to severe rain events.

The eight safety issues reveal problems with preparation and responsiveness to intense rain events nationwide; Auckland and Wellington metro passenger train emergency braking and radio systems and training; and emergency plan if a Wellington passenger train derails.

“Before this accident, shortcomings in KiwiRail’s slope stability assessments meant they didn't know about land above this part of the Kāpiti Line being at risk of land slips.

“After the accident, KiwiRail installed debris protection and live monitoring at the slip site. And with professional advice, KiwiRail is updating its risk assessment tool to help them understand how best to protect slopes along the Wellington Metro network.”

KiwiRail has accepted the Commission’s recommendation for its live rainfall-monitoring and risk systems to provide alerts for intense moderate-to-high rainfall which can cause damage to rail infrastructure.

“If KiwiRail's systems had done this ahead of the Kāpiti Line accident, it's very likely that Train Control would have been alerted and stopped trains.”

The Commission also found safety issues with equipment and driver training in Auckland and Wellington metro passenger trains.

“First, the in-cab main radios should automatically alert Train Control when a driver applies emergency brake; if that happens, then Train Controllers are equipped to keep other rail vehicles away from the site.

TAIC recommended that Transdev Wellington and Auckland One Rail resolve this issue. OneRail has addressed it but Transdev Wellington has it ‘under consideration,’ pending approval and funding from Metlink, which owns the rolling stock.

“This safety issue isn’t new. In 2010, TAIC investigated a passenger train that derailed when it struck a slip on a multi-line section of track. Then another passenger train travelling the other way struck the derailed train. TAIC recommended automatic alerts to train control after emergency braking but it hasn't yet been done.

“Second, we’ve recommended Transdev Wellington review and improve practical training for drivers to apply the emergency radio button when they hit the emergency brake. Transdev has this ‘under consideration’ too.

“When we looked deeper at radio systems, we found patchy coverage along parts of the main trunk line meant Wellington’s Transdev commuter train crews sometimes can't contact KiwiRail Train Control. After this accident, with no power in the cab and a bad local signal, the driver had to resort to a personal mobile phone to reach Train Control. To resolve this, we’ve made another recommendation to Transdev.

The TAIC report details two further safety issues around checking of radios for serviceability.

Finally, the Commission found that Transdev Wellington and KiwiRail had no shared plan (a Triggered Action Response Plan – TARP) setting out how they would work together in the case of a derailment on the main trunk line.

“This created a risk that Transdev train crews and KiwiRail controllers might not always follow a safe process to evacuate passengers. KiwiRail is giving this issue the priority it deserves; it has drafted a new TARP and anticipates its first phase will be implemented across the rail industry by December 2024. For this issue there was no need for a new recommendation.

The Transport Accident Investigation Commission opens an inquiry when it believes the circumstances of an accident or incident have - or are likely to have - significant implications for transport safety, or when the inquiry may allow the Commission to make findings or recommendations to improve transport safety.

The Commission's purpose is to improve transport safety by avoiding repeat accidents, rather than by ascribing blame.

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