Britain’s Rail Accident Investigation Branch has launched an investigation into the derailment of a passenger train travelling at about 77mph in Essex, two weeks after the incident left all 62 people on board uninjured.

The train, operated by Greater Anglia, derailed at about 2:08pm on August 14, around 2.1 miles (3.4km) south-east of Wickford station, while travelling from Southend Victoria to London Liverpool Street.

According to the Rail Accident Investigation Branch in a statement published on Friday, the train was made up of two Class 720 electric multiple units, each consisting of five vehicles.

The rearmost vehicle derailed, after which its wheels ran on the sleepers and ballast for about 1.5 miles (2.4km).

Despite the derailment, the train remained upright throughout, with no reported injuries among the estimated 62 people on board.

The RAIB said preliminary analysis of the train’s on-train data recorder showed that it was travelling at about 77mph (124km/h) when it derailed.

“The driver reported seeing a kink in the track which rocked the driving cab as the train passed over it,” the investigation body said.

It added that forward-facing CCTV recovered from the train showed a misalignment in the track at the same location identified by the driver and where the derailment occurred.

The driver was reportedly in the process of informing the signaller about the condition of the track when an emergency call was received from another train travelling in the opposite direction.

The driver then applied the train’s brakes.

Investigation

The RAIB said its investigation would examine the sequence of events leading up to and during the derailment, as well as the actions of those involved and the factors that may have influenced them.

It will also examine the condition of the track at the location and how it was maintained.

The investigation will specifically consider the effectiveness of measures intended to mitigate the risk of operating trains in hot weather.

The RAIB will further assess the performance of the train during the derailment and investigate any underlying management factors.

The derailed train sustained damage, while the train travelling in the opposite direction suffered minor damage from flying ballast.

The incident also caused significant damage to the track, signalling equipment and overhead electrification infrastructure.

The RAIB stressed that its investigation is independent of any inquiry being conducted by the railway industry or the Office of Rail and Road, the industry regulator.

It said its findings, including any recommendations aimed at improving safety, would be published when the investigation is concluded.

The investigation, according to the release, will therefore seek to establish why the track became misaligned, whether hot weather contributed to its condition and how the train remained upright despite travelling at high speed after the derailment.