Two packed commuter trains collided head-on in the Monday morning rush-hour in the Austrian capital Vienna, leaving five people seriously hurt, emergency services said.In a large rescue operation involving around 25 fire engines as well as air ambulances, many of the injured had to be extracted from the wreckage of the crash using special cranes."At the moment there are five people seriously injured and several people with light injuries," emergency services spokeswoman Claudia Gigler told AFP. "The seriously injured were taken immediately to hospital."The Austria Press Agency reported that one of those seriously injured was one of the train drivers and that there were as many as 20 people suffering light injuries.Austrian automobile association OeAMTC said that one person was trapped inside the wreckage, and that many of the passengers were suffering from shock.It took almost two hours to evacuate both trains, which had been travelling along the same track when the collision occurred at 8:45 am (1315 IST) in the Penzing district of western Vienna.Gigler said the reason both trains were on the same track "remains unclear at the moment".

"Of course we will investigate the causes for the collision but at the moment our priority is with the passengers," Austrian Railways spokeswoman Sarah Nettel said.Last September a train derailed in the same area, without causing any injuries. An enquiry blamed human error for the incident after a rail worker switched a point the wrong way.