An inquiry has been launched into a collision involving a high-speed magnetic train on a monorail that killed 23 people in Germany.
Officials say human error, rather than a technical fault, probably caused the crash near the northern town of Lathen.
The train collided with a maintenance vehicle left on the track on Friday, scattering debris across a large area.
German chancellor Angela Merkel visited the crash site to express her sympathy for the relatives of those killed.
"Words don't really help on a day like this," Ms Merkel told reporters.
"By being here I just want to show that our feelings are here in the region, especially with the relatives of the victims and the rescue workers.
Prosecutors in Germany are examining records of the train's radio communications to explain the cause of the crash.
A communication failure is being seen as the disaster's likeliest cause.
The train, which floats on a monorail via a magnetic levitation system called maglev, was going at nearly 200km/h (120 mph) when it crashed near Lathen.
The impact is thought to have flung the maintenance vehicle along the front and roof of the train.
Two workers were in the maintenance vehicle when it crashed. The train is said to have been carrying 30 passengers, of which 10 survived.
The track's operators say initial checks have not shown any sign of a technical fault.
Rudolf Schwarz, a spokesman for IABG, the Munich-based firm that operates the track, told the Associated Press news agency: "At this time, the accident was not caused by a technical failure.
"It is the result of human error," he said.
The accident happened at about 1000 local time (0800 GMT) on Friday, on a 31.8km (20-mile) test track from Lathen to Doerpen, which is used for tourist trips and to demonstrate the technology.
Damaged carriages were left balancing on track 5m (16ft) above the ground following the collision.
The Transrapid train was developed by a joint venture between the Germany companies Siemens and ThyssenKrupp.
Chancellor Merkel, who helped promote Germany's maglev industry during a visit to China in May, said she did not blame the technology for the crash at this point.
"The technology is a very, very safe technology," the Associated Press news agency quotes her as saying.
The only train of this kind in commercial use is a shuttle linking Shanghai's Pudong international airport with the city.
State-of-the-art maglev technology is capable of driving trains at speeds of up to 450 km/h (270 mph).
But it remains highly expensive and rail operators around the world have been reluctant to use it, the BBC's Tristana Moore reports.
Here are a selection of comments received by the BBC News website:
I have travelled on the MagLev train in Shanghai and it is a truly amazing experience, I hope that the tragic event in Germany does not hamper its development. Paul, Barcelona, Spain
Maglev is expensive to build and operate, visually intrusive and operationally inflexible. While limited applications such as airport people movers or certain point-to-point inter city routes may be appropriate in future, more resources should be committed to developing conventional rail systems. Alan Colquhoun, Warsaw, Poland
Having used the Maglev train in Shanghai, this should not be used as an excuse to delay further development of this fantastic, environmentally friendly piece of technology. This train could offer London - Brighton services in 7 minutes, and further development should continue. Sam, London, UK
What an absolutely tragic and mournful day this has been. Although I'm living several kilometres away from the crash scene, this massive extent of devastation is so gruesome and frightening. Martin, Neuss, Germany
I recently rode the Mag Lev train in Shanghai. I've travelled many forms of transit from the underground to Concorde. I came off my round trip feeling very ill at ease - and I remember saying to my friend that if something were on the track at these speeds we would be finished (which is one reason the tracks are elevated). The feeling is very different from the Japan bullet trains or the French TGV. My heart goes out to the family and friends of those killed and injured. David, Santa Monica, USA
I was in the cab of the Transrapid train during a high-speed run at the test track in Lathen on August 18 in connection with my work as a transport journalist. They showed me some of the maintenance vehicles and I can only imagine it would have been a terrible crash if the train hit one of them at speed. It strikes me that the accident does show a weakness in the technology. If a maintenance train were left on the track on a normal railway, it would be impossible to turn the signal behind it to green. There clearly wasn't any such system at Lathen. Robert, London, UK