The tram that derailed in Croydon killing seven people was travelling at three and a half times the speed limit, investigators have said.
The Rail Accident Investigation Branch (RAIB) said the tram, which was carrying about 60 people, was travelling at 43.5mph in a 12mph zone.
In its interim report, it said there was no evidence of any track defects, or obstructions on the track.
The investigation also found no malfunction of the braking system.
The tram derailed last Wednesday morning shortly after coming out of a tunnel with a 50mph speed limit.