At least four people were killed and scores injured in a train collision in southern German state of Bavaria on Tuesday, police said.Traffic on the railway line, near the city of Rosenheim, was suspended following the accident, Xinhua reported citing the police.The collision caused several carriages to derail. Some of the injured passengers were reportedly in critical condition.A spokesman for German railway company Deutsche Bahn said the two trains collided on a single-track section.Rescue workers and several helicopters were rushed to the scene.The cause of the accident was yet to be ascertained.