During the evening of 28 November 2009, a London to Yeovil train ran into a landslip in a cutting on the eastern approach to Gillingham tunnel in Dorset. The leading carriage of the train became derailed and the train ran into the tunnel and stopped 200 metres inside. The landslip was caused by water overflowing from a blocked ditch at the top of the cutting slope. Two passengers reported minor injuries and the leading carriage of the train and around 450 metres of railway track were damaged.
The immediate cause of the accident was a landslip triggered by water overflowing from a blocked ditch.
The causal factors were: the Victorian cutting design did not take adequate account of the interaction between geology, groundwater and heavy rainfall; roots were not dealt with properly during maintenance work and the person who inspected the ditch did not have appropriate guidance about how to deal with roots; there was no Network Rail process for establishing the drainage ditch condition; and there had been a lack of action in response to an earlier memorandum.
RAIB has made five recommendations to Network Rail relating to management of drainage and earthworks. These include a recommendation to identify, and then adequately maintain, drainage which is required for railway safety but is not located close to the railway tracks.
Response to recommendations:
- RAIB will periodically update the status of recommendations as reported to us by the relevant safety authority or public body
- RAIB may add comment, particularly if we have concerns regarding these responses.