It hit a building and collapsed like a cardboard box

It was just after 18:00 on Wednesday when a carriage on Lisbons famous Gloria funicular came around the bend of a steep cobblestoned street, crashed into a building, and crumpled, an eyewitness said.

"It hit a building with brutal force and collapsed like a cardboard box," Teresa dAvó told Portuguese television channel SIC, adding it seemed like it "had no brakes".

Police are still investigating the cause of the crash, which killed at least 17 people and injured 20 more, some critically, near Lisbons Avenida da Liberdade in the Portuguese capital.

Video verified by the BBC shows the crashed yellow-and-white train on the bend of a hill crumpled against the building, with another train stopped at the bottom. People are running up the incline towards the scene of the crash.

Helen Chow, who is from Canada and was visiting Lisbon, was at the base of the Gloria Hill, from where the trams ascend to the Bairro Alto district, when she said she heard a loud screech.

One tram "made a hard stop, I saw black debris, heard the passengers on that tram screaming…the driver rushed to open the gates to the entrance of the tram," she told the BBC.

"People jumped out of the window of that tram... just as this happened, I saw the incident tram crash over into the building next to the Subway restaurant."

"It was awful… the sound was unlike anything I ever heard," she added. "I am shaken."

Ms dAvó told Portuguese newspaper Observador the vehicle was "out of control, without brakes".

"We all started running away because we thought [the carriage] was going to hit the one below," she said. "But it fell around the bend and crashed into a building."

Eric Packer, from the US but visiting Lisbon on holiday, told the BBC he had discussed with his friends taking the cable car and took pictures at 18:00 and 18:01, but decided to walk back to their hotel instead.

They walked about 60 metres and heard a loud crash noise "like a rock falling, like a dump truck had dropped a load of rocks" at 18:02.

They turned around to see dust coming out of the alley about 45 metres (148ft) behind them and walked back to see what happened. At first, he thought it was the train at the bottom that fell, until he turned and saw the other train that was above it, and realised "the magnitude of what had taken place".

His photograph shows the yellow-and-white train, a tangle of metal, on the corner of the narrow alley under a Subway restaurant sign, with the other train at the bottom of the hill below it.

"People (were) walking up and running up to try and help," he said. "Horrible tragedy and our thoughts and prayers go out to the families and survivors."