At least 35 passengers have been injured, five of them seriously, after two trains collided head-on just outside a station in western Switzerland.
Pictures of the scene showed the two trains still on the tracks with the cabs crumpled into each other and broken glass on the floor of the carriages.
Public TV station SRF quoted state police spokesman Pierre-Olivier Gaudard as saying that one person had yet to be recovered from the wreckage.
News website 20min.ch quoted Patricia Claivaz of the Swiss rail company CFF as saying the trapped man, a driver of one of the trains, had been located, but it was unclear if he was alive.
Ambulances, fire engines and a helicopter were on the scene of the crash at Granges-pres-Marnand in the Vaud canton, around 31 miles southwest of the capital, Bern.
The helicopter and ambulances rushed the five seriously injured to a hospital in the nearby town of Payerne and south to the city of Lausanne. Their injuries were not life-threatening however, police said.
Rescue operations were still under way and specialised equipment has been brought in to try to get to the crushed train cabin faster. But Swiss media reported that rescuers were all but certain the driver was dead.
Rescue teams have deployed a heavy-lifting crane to remove the rest of the wreckage and clear the line.
As night fell, they set up arc-lights to help operations continue.
The collision happened around 100m from a station at 7pm (local time) when one train bound for Lausanne left the station as another, travelling from Lausanne, arrived.
Police said the northbound train was from the faster regional service, which in general stops at fewer destinations than the slower service that covers more local communities along the line.
Police experts, along with members of the Swiss accident investigation authority SESA, have launched an investigation into the likely cause of the crash, officials said.
A CFF spokeswoman said that the two trains should have crossed at the station, thanks to a track system that allows them to pass one another.
It was not clear whether the collision could have been sparked by a delay to one of the trains, or one of them setting off too soon.
Switzerland's rail system is considered among the safest in the world, but three years ago the Glacier Express tourist train derailed in the Alps, killing one person and injuring 42.
Seventy-nine people were killed in a train crash in Spain last Thursday, one of the worst in decades.