The lack of emergency braking by a tram involved in a fatal crash suggests the driver "lost awareness", an investigation has found.
Seven people were killed and a further 51 injured when the tram derailed in Croydon, south London, as it entered a sharp bend at almost four times the speed limit.
Analysis of the on board data recorder shows the regular service brake was not applied until around 2.5 seconds before the tram reached a 20km/h (13mph) speed limit sign at the Sandilands curve where the accident occurred at 6.07am on November 9 last year.
Rail Accident Investigation Branch (RAIB) findings published shortly after the crash gave the speed of the tram as it entered the bend as approximately 43.5mph.
But in a second interim report it stated that the tram only decreased from 49mph to 46mph by the time it passed the speed limit sign. The hazard brake was not used.
The RAIB said: "The late application of the brakes, and the absence of emergency braking, suggests that the driver had lost awareness that he was approaching the tight, left-hand curve.
"The RAIB is continuing to investigate the factors that may have caused this to occur."
The tram driver, Alfred Dorris, 42, from Beckenham, south-east London, was arrested at the scene and questioned on suspicion of manslaughter before being bailed until May.
Around 70 passengers were on the two-carriage tram when it came off the tracks, overturned and slid for 25 metres.
Investigators found that the point at which the bend can be seen and the sign becomes readable in clear conditions is up to 120 metres beyond where a regular full brake must start in order to reduce speed from 50mph (the maximum permitted for trams approaching the area) to 13mph.
But the "readability" of the sign is likely to have been reduced by heavy rain at the time of the crash, the RAIB noted.
The report added: "There was no sign to indicate to drivers where they should begin to apply the brake for the Sandilands curve; they were expected to know this from their knowledge of the route."
London's Transport Commissioner Mike Brown said additional speed restrictions and associated signage were introduced near Sandilands and at three other locations on the tram network before services were resumed on November 18.
In January chevron signs were installed at four sites with "significant bends" including Sandilands to provide "an additional visual cue" for drivers.
Mr Brown added: "Our thoughts remain with all those affected by the tragic tram derailment and we continue to do all we can to offer our support.
"We continue to work with the Rail Accident Investigation Branch and will take on board all recommendations from this and other investigations."
Six men and one woman were killed in the accident. A further 51 people were taken to hospital, 16 with serious injuries.
The RAIB said that of the seven passengers who died, one was found inside the tram, two were found partially inside the tram, three were found underneath the tram, and another was found on the track close to the tram.
A full accident report is expected to be published later this year.