Seven passengers died when a Croydon Tram derailed and overturned on a curve at Sandilands Junction in Croydon on November 9. A further 51 people were taken to hospital - eight suffered injuries described by the London Ambulance Service as “serious or life-threatening”.
The accident happened at 0607. The Rail Accident Investigation Branch’s (RAIB’s) initial review, published on November 16, stated that an initial review of the on-tram data recorder (OTDR) shows the tram was travelling at approximately 43.5mph as it entered the curve.
The maximum speed for the curve is 12.5mph. The maximum speed of the tram is 50mph. When it derailed, the tram travelled for approximately 25 metres before it stopped.
The tram (2551) was operating an ‘inbound’ service from New Addington to Wimbledon via Croydon Junction, having started its journey at 0555. RAIB is trying to determine the exact number of passengers aboard at the time of the accident, but believes it to be around 60.
The only staff member on board was the driver, who is believed to be 42-year-old Alfred Dorris. He was named widely across national media outlets, although RAIB, the Office of Rail and Road (ORR) and FirstGroup (which operates the trams) would not confirm the driver’s identity.
The driver was arrested on suspicion of manslaughter. He was breathalysed following the crash, taken away for questioning, and released on bail ahead of further investigations, reported the British Transport Police. The ORR confirmed on November 15 that he could be prosecuted under Highways legislation, although it would not be the ORR prosecuting.
RAIB explains in its initial review that to be travelling at the permitted 20mph, a tram approaching the Sandilands Junction area from Lloyd Park at 50mph would need to brake at its full service rate of 1.3m/s2 approximately 180 metres before the speed restriction board.
Initial analysis shows that some braking was applied in the 180 metres before the 20mph board, but was only enough to reduce the speed from 50mph to 43.5mph by the time the tram passed the board and entered the curve.
National media has reported that the driver either blacked out or was on a mobile phone at the time of the accident. Sources close to the investigation suggest the latter is more likely, but the initial review did not report a reason.
External circumstances highlighted by RAIB were that it was dark and raining heavily at the time of the crash.
RAIB also reported that Tram 2551 was fitted with forward-facing and internal closed circuit television (CCTV) cameras and an OTDR. The latter records key parameters such as vehicle speed and the driver’s operation of power and brake controls.
RAIB said the OTDR was working at the time, and that evidence taken from that is being used in the investigation. However, an initial examination of the CCTV suggests it was not working at the time of the accident. Additionally, a survey of the track (at this stage) showed no evidence of any defects or obstructions that could have contributed.
RAIB said that a detailed examination of Tram 2551, as of November 16, had not been possible. However, its initial investigation has not indicated any malfunctioning of the tram’s braking system.
In light of the accident, RAIB issued urgent safety advice to Trams Operations Ltd and London Trams. It said: “The factors that led to the over-speeding are still under investigation. Until these factors are better understood, and before the junction reopens to passenger operation, RAIB advises London Trams and Trams Operations Ltd to jointly take measures to reduce the risk of trams approaching Sandilands Junction from the direction of New Addington at an excessive speed.
- For in-depth analysis on this story, read RAIL 814, on sale November 23.