The children were screaming and were in a panic

Lydia Gloeckle, passenger

First reports indicate that human error is to blame for the crash, a German railways spokesman has been quoted as saying.

The train travelling from Lindau should have waited for the second train, travelling in the opposite direction from Friedrichshafen, to arrive before it pulled out of Enzisweiler station.

The two regional Deutsche Bahn trains collided at 0730 local time (0530 GMT).

They were travelling on a single-track line linking Lindau - a town on Lake Constance on the border with Switzerland - with nearby Friedrichshafen.

Terror and confusion

Passenger Lydia Gloeckler said there had been terror and confusion following the impact.

"There was a big bang and I was thrown from my seat along with many children," she told Reuters.

"Then the door was locked, it was stuck and we could not get out. The children were screaming and were in a panic."

Police have yet to determine why the two trains were travelling in opposite directions on the same line.

The rail authorities had for some time been considering laying a second track, according to local media reports.

German and Swiss helicopters flew the most seriously injured to hospital.

Doctors and first aid workers are treating other casualties in tents at the scene.

Safety record

All the injured passengers have now been freed from the tangled wreckage.

The railway line is expected to remain closed for the rest of the day.

The crash comes less than three years since Germany's worst-ever rail disaster, in which 101 people died when a Deutsche Bahn inter-city express smashed into a bridge at Eschede in the north of the country.

In June, seven people were killed in two separate train crashes.