The U8 train travelling in the direction of Hermannstraße left the platform and dragged the child 60 to 70 metres into the tunnel. The train finally came to a halt because passengers pulled the emergency brake.
An emergency doctor attended to the child on site before she was taken to hospital. The police said the child suffered a fractured arm and severe head injuries.
Emergency counselors were called after the accident and tended to several witnesses who were in shock. The girl's eight-year-old who witnessed the accident suffered a severe shock and also had to be taken to hospital.
According to the police, train service on the U8 line was interrupted for about two hours.