Digital image correlation of overhead line equipment to reduce clearances at structures

Data can drive efficiencies in asset management strategies. However, conventional structural health monitoring can be onerous as it requires separate surface contact sensors to measure strain, deformation, rotation and displacement. Identifying an opportunity to develop on emerging technologies, AtkinsRéalis adopted digital image correlation (DIC) technology for outdoor structural monitoring purposes. DIC uses camera technology to generate the same insights, without requiring sensors installed on the structure, providing a more cost-effective, sustainable, safer and less disruptive solution. With a clear line of sight, the camera can be positioned hundreds of metres from the asset. In the case study presented in this paper, this removed the need for track closures, working at height or close to moving trains. In this paper, the use of DIC for overhead line equipment (OLE) uplift measurements to permit the development of new rules for OLE designers working at open-route locations on future electrified routes is explored, and a case study of a large-scale project to measure open-route OLE uplift at ten UK sites is presented. The benefits of adopting this data-driven approach are clear and the associated benefits of DIC use in this context, such as cost savings, minimising passenger disruption and reduction of embedded carbon dioxide, are discussed.