A double-decker commuter train accident at Alcala de Henares station in Spain on December 22 left at least four people seriously injured and another 45 sustained minor injuries.

Transit company Renfe has launched an investigation into the cause of the accident, and said the Cercanias train was traveling at ‘very low speeds’ when the accident occurred, and the driver tested negative for drugs and alcohol.

Alcala de Henares Mayor Javier Rodriguez was on the scene of the accident. Credit: Twitter/Raphit Tejeda via Storyful