VIENNA (REUTERS) - Forty-one people were hurt - five of them seriously - when two crowded commuter trains crashed head-on in Vienna during the morning rush hour on Monday.

The driver of one train and another person remained in critical condition after the mishap, according to the emergency services in the Austrian capital.

Operations on the line had been switched to manual following a technical defect with a shunting switch, and a spokesman for Austrian railways said human error had not been ruled out as a possible cause of the crash.

"A train got permission to travel when it should not have," she said.