The derailment occurred early in the morning of 23 January, when one pair of wheels on a freight train travelling from Barking to Calvert became derailed on a bridge near Wanstead Park station.
The Rail Accident Investigation Branch said the train of 22 wagons was carrying construction soil to Calvert, and had travelled a further 4km before the braking system alerted the driver of the Class 66 locomotive. The train was then brought to a stand between Leyton Midland Road and Walthamstow Queens Road stations.
The derailed wagon had left a trail of destruction as it careered along, and Network Rail has had to replace 39 sections of rail, 5,300 concrete sleepers and 900 wooden sleepers. The timbers on 10 bridges were also damaged, and needed specially-made replacements.
Anglia route director Ellie Burrows said: ‘Repairing and effectively rebuilding the railway has been an absolutely mammoth task for our engineering team, but along with great support across the industry and supply chain, I’m happy that train services can return to normal. I am acutely aware of the disruption this has caused for passengers and our lineside neighbours and I’d like to say thank you for bearing with us while we completed the work.’
RAIB inspectors are now examining the condition, inspection and maintenance of the track, including the longitudinal bridge timbers, as well as the condition, maintenance and loading of the wagon concerned. Inspection procedures will also be assessed.
The cost of the repairs and resulting disruption has not been revealed.