Aerial surveys of all earthworks assets could eventually be used in place of physical inspections within five to eight years, says Network Rail.
Analysis of the national aerial surveys undertaken by Network Rail’s offering rail better information services (Orbis) programme last summer are already providing vital information to earthworks maintenance.
The Orbis initiative has driven wider use of iPads and in-house development of more than 60 apps to collect and manage data, which Network Rail believes will drive £700M of efficiencies over the next 10 years.
Network Rail head of geotechnics Simon Abbott believes that Orbis’ high resolution surveys offer the potential to deliver a step change in the monitoring and assessment of earthworks assets and add further efficiencies.
“The survey was originally conceived to look at vegetation compliance issues but we were able to influence the specification, which has led to the surveys being undertaken at a resolution we can use for earthworks monitoring,” said Abbott.
According to Abbott, resurveying areas of troublesome areas could help Network Rail’s earthworks engineers ongoing trends and deterioration, as well as identifying changes on third party land close to Network Rail assets.
“Currently we physically inspect assets periodically but this can be subjective, whereas use of the survey data would allow the assessment to be more objective,” he explained. “If there is a real concern about a site then we should always revert to manual and visit the site.”
The Orbis survey cost £16M to undertake but Abbott does not believe that these costs are prohibitive to surveys being undertaken annually. “We currently spend around £20M per control period on inspection and a further £10M to £15M on vegetation clearing to enable the work,” he said.
Abbott believes that the use of aerial surveys could run in parallel with CP6 and start to deliver real benefits and efficiencies in CP7. “The challenge the geotechnics industry needs to tackle to achieve this is how to manage big data,” he added.
In the meantime, Abbott has said that Network Rail is making the aerial survey data available for use on current projects and contractors and consultants should ask for the data.
Abbott added that further efficiencies could be delivered by greater integration of other data sets into earthworks asset assessment, such as track data. “Essentially they are horizontal inclinometers,” he said. “The challenge is interpreting the data as cyclical maintenance can mask the actual movement.”