Dozens were injured in Germany on Tuesday evening after a freight train collided with a passenger train carrying 155 people near Duesseldorf city. Of the 47 people hurt, three sustained serious injuries and three “medium” injuries, the local fire department said on Twitter.

The collision took place around 7.30 pm local time near the Meerbusch-Osterath station in West Germany. The cause of the accident is not clear yet.

After a rescue operation that ran for four hours, the fire department said it had taken all passengers out of the train. The injured were taken to hospital.

The driver of one of the trains had “noticed an obstacle on the track and immediately hit the emergency brake”, a spokesperson for British operator National Express, which runs the train, told the Bild. The driver was unharmed but in shock.

Chancellor Angela Merkel is “following the situation closely”, her spokesperson Steffen Seibert said on Twitter.