According to a New York Times report, witnesses described being suddenly thrown out of their seats and landing in piles in the center of the railcars as three cars near the front of the train derailed and jackknifed. The cause was not immediately clear. However, the news agency Interfax cited an unnamed official described as being close to the investigation saying that a truck had come loose from the undercarriage of a railcar near the front of the train, causing that car to come to a sudden stop, with some cars behind also derailing.
The derailment closed the Moscow metro’s heavily traveled Arbat-Pokrovsky line, which bisects the center of the city. Authorities said it would take at least 24 hours to clear the debris and restore service.
An unidentified passenger described a “sudden braking, the lights went out, sparks, and heavy smoke. Everybody was thrown to one side.” Firefighters reached the wreck within minutes. At street level, rescue personnel evacuated some of the injured in helicopters to avoid morning rush-hour traffic jams.
The accident was the worst loss of life in Moscow’s metro system since 2010, when twin suicide bombings carried out by female terrorists from the region of Dagestan killed 39 people during a morning rush hour. Terrorism has been ruled out as the cause of this accident.