At around 10:26 hrs on 14 February 2016, a passenger train collided with a conveyor boom projecting from an aggregates train standing in sidings at Barrow-upon-Soar, Leicestershire. The train was travelling at approximately 102 mph (163 km/h).
Two of the coaches of the train were damaged by the impact but the train did not derail. The unloading wagon conveyor boom was also damaged. A fitter, who had been working on the conveyor, was seriously injured. Nobody on the train was injured.
The wagon involved in the accident was part of a train which had been loaded with aggregates ready for departure the following day. While checking the operation of one of the wagons in the train, the fitter identified that it needed maintenance.
During the maintenance activity a subsequent failure occurred in the control circuit; a push button switch controlling the movement of the boom became stuck in the ‘on’ position. This caused the boom to fully rotate and, because of the location of the siding in which the maintenance was being undertaken, this placed the end of the boom foul of the nearest of the main lines. There was no instruction to prevent the wagon being maintained on this siding. The risk assessments undertaken in support of the systems of work adopted at the site had not considered the risk of the boom moving out of control and affecting other train operations.
It is probable that the contact block of the push button switch became stuck due to corrosion deposit obstructing its moving parts. This was most likely due to the contact block being exposed to environmental conditions for which it was not designed.
The underlying causes of the accident related to the maintenance of the electrical system of the wagon, and the management of the associated safety risk.
As a result of this investigation, RAIB has made four recommendations relating to:
- Tarmac’s (the owner of the wagon) and Wabtec’s (the maintainer) processes for hazard identification and risk assessment
- Wabtec’s management arrangements and procedures at Barrow-upon-Soar
- Tarmac’s processes for determining when it is necessary to implement interim safety measures after it becomes aware of deficiencies in the condition of its wagons
- Restoring the condition of the wagon’s electrical system, should the wagon re-enter service.
Three learning points are also noted relating to the responsibilities of Entities in Charge of Maintenance and vehicle registration holders.
Simon French, Chief Inspector of Rail Accidents said:
This investigation highlights the vital importance of wagon maintenance to the continued safe operation of freight trains on the UK’s railways. In this case, the condition of the electrical system used to control a wagon-mounted unloading boom had been allowed to deteriorate to the point where reliable operation could no longer be assured. An absence of adequate maintenance led directly to the boom slewing into the path of a passing express passenger train.
This is not the first time the RAIB has identified poor wagon condition as a factor in an accident. In the last two years the RAIB has investigated four freight train derailments where the condition of a wagon was a factor. An example is our investigation into the derailment at Washwood Heath in March 2015 (report 01/2016) which revealed that excessive wear on the bogie centre pivot liner had not been detected by the maintainer.
Since May 2013, it has been a legal requirement that every freight wagon is assigned to a body that is certified to act as the ‘entity in charge of maintenance’ (ECM). Each ECM is required to establish a system of maintenance that ensures that all vehicles for which it is responsible are safe to run on the railway network.
Our investigations into the accidents at Washwood Heath and Barrow-upon-Soar have caused me to question the extent to which ECMs have really understood the implications of what is now required of them. Of particular concern in both cases was the lack of proper understanding of the activities that were required to keep the wagon in a fit condition to run, and the consequent absence of a suitable system of maintenance.
ECMs now play an important role in the rail industry’s management of risk. To meet this challenge they need to ensure that they properly understand the characteristics of the wagons for which they are responsible, and their maintenance requirements. They must also consider the potential consequences of equipment failure and fully assess the associated risks. It is vital that ECMs understand the point at which a wagon becomes unsafe to operate and should be withdrawn from service – and that there are robust processes in place to prevent the operation of a wagon once it has reached this point.
Our investigation into the accident at Barrow-upon-Soar identified the absence of proper maintenance systems to cover the wagon’s electrical components. It is important that ECMs ensure that they establish a maintenance system that encompasses all components on a wagon. Such a system will need to consider all of the hazards associated with the electrical systems – this should never be limited to the risk to maintainers (eg electric shock and fire) but also the potential for wrong side failure leading to an unsafe outcome or the failure of a safety function to operate (such as emergency stop).
Notes to editors
- The sole purpose of RAIB investigations is to prevent future accidents and incidents and improve railway safety. RAIB does not establish blame, liability or carry out prosecutions.
- RAIB operates, as far as possible, in an open and transparent manner. While our investigations are completely independent of the railway industry, we do maintain close liaison with railway companies and if we discover matters that may affect the safety of the railway, we make sure that information about them is circulated to the right people as soon as possible, and certainly long before publication of our final report.
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Newsdate: 27 October 2016