At about 10:48 hrs on 25 January 2008, the tenth wagon of freight train 6M49 - the 09:02 hrs service from Immingham Docks to Rugeley Power Station - derailed on a plain line at Santon, between Wrawby Junction and Foreign Ore Branch Junction, Scunthorpe. The front four wheels of the wagon, which was loaded with coal, left the rails, and the train continued for just over a mile before stopping. No one was injured in this derailment, but there was considerable damage to the railway infrastructure and the line was subsequently closed for over a week while repairs were carried out.
RAIB’s investigation identified that the immediate cause of the accident was that the front right-hand wheel of the wagon rode over the rail as the train traversed a left hand curve at Santon. This was because the load on this wheel was significantly reduced by the combined effect of a number of track geometry faults close to each other. The local Network Rail inspection and maintenance regime had not detected that these faults, which had been addressed by maintenance action three months prior to the derailment, had re-occurred.
The track geometry was deteriorating rapidly because of considerable amounts of water running in the formation beneath it. No-one reported or responded to the signs of water and poor drainage around the point of derailment. The load on the first wheel to derail was also reduced by coal being unevenly loaded in the wagon.
As a consequence of this accident, RAIB has made eight recommendations targeted at the infrastructure owner Network Rail relating to track inspection and maintenance standards, track drainage at Santon, the identification of the exact location of rapid track deterioration, the monitoring of track repair quality and guidance about action to take if water affects the track.
One further recommendation to address the uneven loading of the wagon is targeted at Freightliner Group Limited.
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.
Published 10 December 2014