Report 25/2008: Management of existing earthworks
Network Rail’s management of existing earthworks.
RAIB has previously investigated incidents at Oubeck in November 2005, Moy in November 2005 and Kemble on 15 January 2007 where earthworks slope failures resulted in passenger train derailments.
These incidents were in part caused by a recent period of localised extreme weather, deficiencies in the performance of the local drainage systems at the site and surface water standing on, or flowing from, adjacent non-railway land.
As a result RAIB decided to investigate Network Rail’s overall process for the management of its earthworks.
There has been no fatality attributed, either directly or indirectly, to an earthworks failure since 1995. Though the approach to earthworks management taken by Network Rail is comparable or better than other industries with similar type of earthworks, RAIB’s investigations have highlighted some inconsistencies in the application of earthworks management systems across Network Rail.
The investigation sought to address a number of questions, including:
- Does the available evidence indicate an increasing number of safety related incidents occurring as a result of earthworks failures?
- Are the earthworks management systems used by Network Rail appropriately identifying the safety risk?
- How do the processes and systems used by Network Rail compare with those used by the owners of other, similar infrastructure?
- Is there any evidence of climate change affecting the behaviour of earthworks and if so how is Network Rail addressing this?
Within this report RAIB has made four recommendations targeted at Network Rail which relate to work by them to further understand the accuracy and effectiveness of their inspection and assessment processes in mitigating the risk from earthworks failure, improving the consistency of application of good practice seen during this investigation, the provision of guidance to staff in regard to the railways’ neighbours and the alignment of internal procedures which define the actions to be taken in adverse weather.
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.