The LNE&EM route Structures asset management team is trialling the use of unmanned aerial vehicles (UAVs) to inspect large structures in a safer and more cost efficient way.

The vehicles, commonly known as drones, are being used to get a closer look at five arch viaducts on the route, including the Grade 1 listed, 28-span Royal Border Bridge in Berwick-upon-Tweed, Northumberland.  

Since 2017 the Structures team has been working alongside AECOM consulting engineers, Network Rail’s Air Operations team and Cyberhawk – a company that operates UAVs – to carry out the inspections, gaining a panoramic bird’s eye view of the structures. 

With an increasing number of structural assessments, including of many arch viaducts, the team had identified a need for a more efficient inspection method to supplement the more traditional access techniques typically used. 

Terry Donaldson, scheme project manager, Network Rail, said: "UAVs are commonly used in other industries such as oil and utilities to inspect their structures, such as pylons and oil rigs. We thought ‘why not try them out?’

"As well as being cost effective, this innovation has reduced the need for possessions, track access and roped access, reducing safety risk.  

“The quality of the information our asset engineers have received has also been much better than what can normally be produced with standard inspection techniques."

The high-definition images captured by the UAVs will be examined by asset managers. Previously, photographs would be taken by the engineer as they carried out the inspection at height – abseiling down the structure, often in the dark and poor weather – with views limited to where the person could reach and see.  

As well as delivering a more comprehensive 360 degree view of the structures, in daylight and showing all the defects clearly, the UAV images are being stitched together with photogrammetry to create high quality 2D elevations, 3D models and also cloud point surveys (avoiding the need for a separate dimensional survey).