Two trains collided head-on killing ten people and injuring more than 100 near Bad Aibling, about 60 kilometres southeast of Munich in Bavaria.
German Transport Minister Alexander Dobrindt told a press conference that the two trains belonging to regional train company Meridian were travelling at 100 kilometres per hour on a single-track route. The crash happened at 7am.
"It is difficult to understand how the crash took place despite so much investment in railway safety after the previous crashes," Bavarian Interior Minister Joachim Herrmann told the same conference.
The operator said the collision took place on a bend between Rosenheim and Holzkirchen. Two of the three data recorders (black boxes) on board have been recovered.
The two trains wedged into each other and one side of a train was ripped open, Dobrindt said, adding that the line had an automatic braking system designed to stop a train if it passed a stop signal.
Emergency teams brought in by helicopters rescued the injured from the site in a forested region close to the Mangfall river.
It is likely because of the bend the drivers would not have seen the trains approach on a collision course.