Formal Inquiries

Nailsea report and recommendations

Rail Safety and Standards Board (RSSB) has issued its formal inquiry report into the circumstances that led to a serious fire on board a passenger train at Nailsea, North Somerset on 18 October 2004.

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

The 20:06 hrs Bristol Temple Meads to Weston-super-Mare train comprising two diesel multiple units departed on time. After passing through Flax Bourton Tunnel, two passengers drew the conductor’s attention to unusual noises, smells and eventually smoke coming from below the rear vehicle of the train.

The train was brought to a stand by the driver, about half a mile short of
Nailsea and Backwell Station. The passengers detrained onto the cess and during this process one passenger made a 999 call to alert the emergency services. The fire that had developed in the rear vehicle was eventually brought under control by the Avon and Somerset County Fire service, but not before very considerable damage to the vehicle had occurred. Two passengers and the conductor were treated for smoke inhalation in an ambulance at the site. No other injuries were reported.

Conclusions

The panel concluded that the fire was due to electrical arcing between the live starter motor cable, with damaged insulation and the underframe, causing accumulated oily residues to ignite. Other fuel sources then subsequently fed the fire.

Underlying causes:

Many fluid connections on diesel multiple units engines are prone to develop leaks.
Physical access to the engine area of the Pacer units is difficult and this seriously hampers the maintenance of leak free connections and engine cleanliness.
Damage to the insulation of starter motor cable was not detected by the examination techniques in use.
Standards and methods of cleaning of engines and underframes were not adequate and did not always appear to have been independently checked.
A fire suppression system that effectively covers the engine but not the vehicle underframe.

Recommendations

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

Review techniques, equipment and facilities for underframe cleaning and produce a best practice guide. This should be complemented by the development of inspection techniques and standards for underframe cleanliness.
Determine the practicality and effectiveness of installing detachable bodyside panels.
Extension of anti-damage sleeves on starter motor cables to be considered.
Practicality of avoiding starter motor cables that are permanently live with no short circuit protection should be considered.
Fitting of automatic fuel shut-off valves which are activated by the fire detection system should be considered.
The principal fluid joints that contribute to leakage around engines should be identified and concerted efforts devoted to developing leak free solutions where practical.
The records of work done to correct faults identified during train maintenance must be comprehensive in detailing the measures taken and be formally closed out.
Region Control must take responsibility for directing emergency services to the most appropriate access point for an incident and must have available, and routinely use, emergency plans for this purpose.
Documentation must be amended to reflect the limited cleaning and inspection of underframe areas that is possible with current depot facilities.
Methods of providing train crew with hands-on training and experience of using train-borne emergency equipment should be re-considered.
Review of procedures dealing with the return of staff to duty after being involved in an incident.

RSSB 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. RSSB will track the industry's response to this report.