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Formal Inquiries

Huddlesford report and recommendations

Rail Safety and Standards Board has issued its formal inquiry report into the derailment of a freight train at Huddlesford on the 15 July 2003. The formal inquiry was convened under independent chairmanship and included representatives on the panel from the involved parties. As with all such inquiries the panel's task was to establish the immediate and underlying causes of the accident and make recommendations to prevent or reduce the risk of recurrence.

Sequence of events

Train 4L92, a Freightliner service from Ditton to Felixstowe, was derailed at approximately 115 miles 280 yards on the West Coast Main Line between Lichfield and Tamworth.

The train was hauled by a Class 90 locomotive and was conveying 22 vehicles, 15 of which were empty and the remainder laden to differing extents. Derailment took place immediately south of underbridge number 95 at Huddlesford. The eighth and ninth vehicles derailed rear bogie only and the following vehicles derailed all wheels. The train divided between the eleventh and twelfth vehicle and the locomotive came to a stand some 740 metres after the point of derailment with the eighth vehicle having travelled some 566 metres in the derailed condition.

Conclusions
The panel found a number of underlying and immediate causes surrounding the derailment, these were:

  • Train 4L92 derailed immediately south of underbridge number 95 at Huddlesford in response to a significant lateral misalignment of the track.
  • The lateral misalignment was a heat induced buckle and resulted from a probable low stress free temperature and a combination of individual track features. Each of the track features in isolation was unlikely to be sufficient to trigger a buckle.
  • Derailment occurred at 1638hrs approximately on a very hot and sunny day with rail temperatures in the region of 40°C.
  • There were indications that the stress free temperature at the point of derailment was below the specified design values.
  • The shoulder ballast profile over underbridge number 95 and immediately to the south was deficient.
  • There were voids of the order of 4 to 6mm below the sleepers immediately south of underbridge number 95.
  • There was poor vertical track geometry and cross level variation over underbridge number 95 and immediately to the south.
  • The track over underbridge number 95 comprised hardwood timber sleepers that has reduced lateral stability by comparison with concrete.

Recommendations

The report makes recommendations for improvements in a number of key areas and these are summarised as follows:

  • The Project Maintenance Strategy defining the responsibilities of the maintenance contractor, renewal contractor and Network Rail should be reviewed for adequacy. In particular it should encourage timely maintenance of newly installed track so that defects are not allowed to develop closer to safety limits than is desirable.
  • The revised Project Maintenance Strategy defining the responsibilities of the maintenance contractor, renewal contractor and Network Rail be fully briefed and implemented for track renewal sites on the West Coast Main Line (South).
  • Individual relatively minor defects can often have much greater significance if they occur in combination. The recording of all minor track defects should be encouraged so that they can be viewed as a complete picture.
  • Timber sleepers are common in both new and existing CWR. Some installations are very short, that is a few sleepers. There should be clarity and consistency with regard to the assumed stability of such CWR.
  • The effect on rail stress in CWR as a result of major disturbance such as occasioned by ballast cleaning should be assessed.
  • RT/CE/S/011 should be reviewed to clarify the position with regard to locations where a full ballast shoulder cannot be installed.
  • A review of the robustness of the Fastclip fastening system to damage from derailed vehicles and the potential safety consequences should be undertaken.

Rail Safety and Standards Board has issued a full copy of the report to each member of the Railway Group and the other organisations involved in the accident. All recipients of the report need to review the findings and recommendations and take actions where appropriate to address identified deficiencies within their own systems. Rail Safety and Standards Board will track the industry's response to this report.