14.11.16
NR criticised for lapsed safety system following Lamington Viaduct probe
Network Rail failed to address the risk of scour on the Lamington Viaduct, which was closed following flood damage this winter, despite problems being reported for over 10 years, a report by the Rail Accident Investigation Branch (RAIB) has found.
Serious deformation of the track on the viaduct, which crosses the River Clyde between Lockerbie and Carstairs, was reported by a train driver on the morning of 31 December 2015.
The viaduct was closed for more than seven weeks, although it reopened ahead of schedule on 22 February after repairs by Network Rail engineers.
The viaduct’s central river pier had been partially undermined by scour following high river flow the previous day.
The RAIB found that Network Rail had carried out an initial assessment in 2005, which categorised the viaduct as a high priority scour risk because it spans a river bend, which causes water to wash against the sides of the piers, and has shallow foundations.
However, a detailed scour risk assessment was not then carried out until 2013. In January 2015, Network Rail approved a scour protection scheme for the site, but in August, Network Rail Infrastructure Projects requested the authority to defer the project until the next financial year due to environmental permissions not being sought in time for the work to be completed during the low flow summer period.
Simon French, chief inspector of rail accidents, said: “It is of particular concern to me that the vulnerability of this structure to scour had been identified at least 10 years previously. Despite this, insufficient action had been taken to protect the piers from scour, or to monitor the integrity of the viaduct at times of high water flow.
“The continued operation of trains over this high risk structure, despite a previous report from a driver of a rough ride, provides vivid evidence that the risk of scour was not generally appreciated by those involved.”
He added that he wanted Network Rail to think carefully about what it needs to do to assure itself that “any emerging gaps in its asset management regime are detected, and then corrected, long before there is a risk to the travelling public”.
French did note that it was “encouraging” that Network Rail was working towards greater use of remote sensing equipment to monitor the condition of structures.
The RAIB advised Network Rail to review and improve the management of scour risk by the semi-autonomous Scotland Route.
It also recommended that the infrastructure owner should review, and if necessary, enhance its processes for operations staff responding to defect reports in structures over water, which can suffer damage that is not immediately apparent.
Furthermore, it said Network Rail should look at its management and assurance systems for all control centre processes relating to the safety of railway infrastructure used by the Scotland Route.
Network Rail had an extreme weather plan, but it emerged that, since the incident at Lamington, this was not in operation throughout Scotland Route, with no effective scour risk mitigation for over 100 other structures on the high risk and at risk list.
The RAIB investigation also found that the decision, in 2012, to devolve responsibility for day-to-day operation of the rail network to eight strategic routes had contributed to the problem.
It meant that staff knowledge and ownership of some infrastructure issues had been lost. In addition, Scotland Route did not prioritise funding scour protection work in CP4.
The ORR is currently holding a consultation on options for greater route devolution, and the Scottish government has called for full devolution of Network Rail in Scotland.
A Network Rail spokesperson said: “We worked closely with RAIB as it completed this report and will carefully review the findings.
“The safety of passengers, and rail workers, is of vital importance to Network Rail and we have already made significant changes to our management and maintenance of scour-risk structures in Scotland since Lamington.”
They said Network Rail has invested over £3m so far to reduce scour-risk at high priority structures, carried out 277 specialist underwater examinations to assess the foundations of bridges ahead of this winter, and identified 50 bridge sites where it will monitor the impact of flooding.
A recent two-part RSSB report warned the British rail network to prepare for the impact of more disruption as a consequence of extreme weather linked to climate change.
Have you got a story to tell? Would you like to become an RTM columnist? If so, click here.