The Chatham-Kent Police Service said the vehicle was struck by a freight train in the area of Base Line and Industrial Road, just before 8 p.m. on Sunday.
The driver, a 48-year-old Dresden man, was taken to the Chatham-Kent Health Alliance to be treated for non-life-threatening injuries.
The passenger of the vehicle, a 50-year-old Dresden man, suffered critical injuries and was taken to Four Counties Hospital in Newbury before being airlifted to a hospital in London. He remains in hospital in stable condition
The Chatham-Kent police Traffic Unit and the Canadian Pacific Railway are continuing to investigate the incident.
Anyone with information regarding the collision is asked to contact Constable Lisa Rodger at lisaro@chatham-kent.ca or 519-355-1092.