The Tangiwai train disaster, which occurred at about 10:21 p.m. on December 24, 1953, near Tangiwai on the North Island, is New Zealand’s worst rail accident.
This calamity began when a railway bridge over the Whangaehu River collapsed, causing the 3 p.m. express train from Wellington to Auckland and carrying 285 passengers and crewmembers to derail. Its consist included a KA class steam locomotive and eleven carriages: five second-class carriages, four first-class carriages, a guard’s van and a postal van.
The locomotive and the first six carriages plunged into the river, killing 151 people.
A board of inquiry determined that the disaster was triggered by the collapse of a tephra dam that had formed around the crater lake of Mount Ruapehu, a stratovolcano.
Following the dam’s collapse, water and volcanic debris, known as a lahar, was released and surged down the Whangaehu River. Shortly before the train arrived, it destroyed one of the bridge’s piers at Tangiwai, leading to its failure.
