A leading bridge expert this week called for a review of brick parapets on thousands of road bridges across railway lines after a concrete mixer crashed onto a train at Oxshott in Surrey.
Seven people narrowly escaped death when a heavily laden concrete mixer smashed through a brick parapet and fell 10.5m onto the roof of the South West Trains 15:05 Guildford to London Waterloo service. One of the train passengers and the lorry driver sustained serious injuries.
As NCE went to press it was unclear what caused the lorry to crash into the bridge’s parapet, shortly after 3.30pm on Friday.
The lorry was travelling south along the A244 in Oxshott, a heavily-trafficked cut-through from the A3 towards Leatherhead. As the two-lane road crosses the bridge there is no footpath on the nearside.
The Rail Accident Investigation Branch (RAIB) has launched an inquiry into the incident.
Richard Fish, a past chairman of UK Bridges Board and an independent bridge consultant, told NCE that it was likely there would be a review of masonry parapet bridges over railways to assess the risk of similar occurrences.
The RAIB’s investigation will attempt to identify the sequence of events before, during and after the accident. RAIB inspectors will liaise with Surrey Police’s road traffic accident investigators to understand the events on the highway that led to the collision with the parapet. The investigation will also examine the measures taken to manage the risk of vehicle incursion at this location and at similar bridges elsewhere on Britain’s railway network.
Fish said that efforts to understand how masonry parapets, particularly those constructed in Victorian times, react to a collision were “a bit of work in progress”, but added that in a collision with a full concrete mixer “there’s little that could be done with it”.
“Something needs to be done for parapets”
He added: “This is something that needs to be done for parapets. Highways agencies and Network Rail need to look at the risk basis.” He said that the review was likely to look at the bridge parapets, building upon the work done following the Selby rail accident in February 2001. Then, a vehicle came off the M62 motorway on the approach to a bridge across the East Coast mainline before ploughing onto the track. It was hit by a passenger train and 10 people died.
A review of all road-rail interfaces in the country was launched after the Selby crash.But this focused on bridge approaches, rather than the structure of the bridges themselves.
This was because a key factor in the Selby crash was that the crash barriers, which were in place to stop cars getting onto the railway, did not extend far enough away from the structure.
Fish said there was now a need to examine masonry parapets on rail bridges.
He added that without a national bridge database it is impossible to say how many bridges similar to the one at Oxshott there are. But he estimated that it would be between 4,000 and 5,000. Overall, there are 6,500 sites where public road bridges cross railways, including London Underground and private rail lines.
Following the Selby crash, around 10,000 high risk sites where vehicles could come onto railway lines were inspected on 10 different factors, and given a weighted score to assess where the risk was highest. Scores included factors such as the road gradient and bends, and the likely excess speed of traffic in any circumstances.
Sites scoring more than 100 were “clearly inadequate”, a Department for Transport (DfT) report said, indicating that road authorities should seriously consider building a safety barrier appropriate to the type of site and type of traffic.
Network Rail is responsible for the maintenance of the Oxshott bridge structure, including the parapets, which it said that had passed the scored inspection.
Surrey County Council added that following the assessment, the Oxshott bridge was found to be low risk, and no work was judged to have been necessary to install extra protection.
Residents: bridge an “accident blackspot”
But local residents told NCE that the Oxshott bridge was a known accident blackspot. The speed limit falls from 40 miles an hour to 30 miles an hour on the approach to the bridge and road dips and curves left as southbound traffic approaches.
The local authority played down residents concerns, saying that there had only been three recent accidents on the bridge.
UK Bridges Board chairman Mike Winter said the findings of any review must be put into context. He said it was unlikely that ring-fenced money would be available for any improvements, and that the risk had to be assessed against other safety improvement plans on highways.
Government statistics show that 2,222 people were killed on British roads in 2009.
The DfT’s report into the Selby crash, called for authorities to “normally consider a level of containment sufficient to stop a car from reaching the rail line”.
The train itself – formed of two four-car class 455 electric multiple units – survived relatively intact.Severe crush damage was caused to the leading end of the 6th coach and in addition one side of the 7th and 8th coaches suffered severe damage caused by heavy contact with parts of the lorry. The last bogie on the train became derailed.
Selby rail crash
The Selby rail crash took place on 28 February 2001 when Land Rover driven by Gary Hart came off the M62 motorway at Great Heck.
It ran down the railway embankment and onto the East Coast Main Line, where it was struck by a passenger train, which derailed and was struck by a freight train travelling in the opposite direction. Ten people died after what the Health & Safety Executive said was highly unlikely and unpredictable chain of events. A report by consultant TRL found that the safety barriers met the requirements of the national standard.
Subsequent reports by from the then Health & Safety Commission and the Highways Agency produced 19 recommendations to government. As a result, risk assessments of road/rail interfaces were undertaken, to prioritise the riskiest locations where more protection should be put in place.
In 2001, Hart was sentenced to five years prison for causing the 10 deaths by dangerous driving.