Passengers onboard a train that derailed at Auckland's Britomart Station initially thought the incident was an earthquake, or even possibly a shooting.
Three carriages derailed as the train was leaving the station, trapping passengers for about 40 minutes.
Passenger Charles Stewart said everything was going smoothly and then there was a sudden shake "like a small earthquake" as the train came off the tracks.
Another woman said, "We thought there might have been a gunman or something".
It was "really annoying" that more information was not provided before the passengers got off the carriage, she said, as they had no idea how long they would be there for.