The Rail Accident Investigation Branch (RAIB) has completed its investigation into a freight train derailment earlier this year.

On January 23, two wagons on a heavily loaded 22-wagon freight train derailed as the driver was passing near Wanstead Park.

The train was going round a curve on a bridge between Woodgrange Park and Wanstead Park at 5.54am, when two wheelsets from two wagons came off the track.

One of the wheelsets brought itslef back onto the track, but the other remained derailed for two-and-a-half miles at a speed of up to 35mph before the train eventually came to a stop, after the brake pipe between the two affected wagons separated, causing the train brakes to apply automatically.

Fortunately, no one was injured but significant damage was caused to the track - the railway between Woodgrange Park Junction and South Tottenham East Junction was closed for repairs for 27 days.

East London and West Essex Guardian Series:

Examples of some of the damge caused to the track following the derailment. Credit: RAIB

During its investigation, the RAIB learned that the “forces” from the train caused the rails on the bridge to spread apart, causing the derailment.

The rails are supported on longitudinal timbers but close inspection found the condition of the timbers at the point of derailment had “severely deteriorated because of rot”.

The investigation report indicated the “weakened track” was unable to support the force of a wagon.

East London and West Essex Guardian Series:

The bridge where the wagons derailed. Credit: RAIB

At the time of derailment, the train was running at 22 mph - there is no indication that the handling of the train had any influence on the cause of the derailment.

But examination of the first wagon to derail and its maintenance records indicated it had experienced “unusually rapid wheel wear over several years”, the report added.

The report states Network Rail were made aware of the widening of the track six times between March 2019 and January 2020.

On three occasions, the track maintenance team responded but carried out work in the wrong place due to a GPS error, while on three other occasions, the location of the fault was not recorded properly so maintenance staff remained unaware of the problem.

RAIB made one recommendation to Network Rail regarding improvements in tracking maintenance calls, while a recommendation was given to the wagon owner about reducing the risk of using “defective” rail vehicles.

Read the RAIB's full report here.