A survey control network was created, with a survey grid related to the OS National Grid and Datum. Survey Control and UAV control was established in the cess (the bit at the side of the track).

Flying at a working height of 25m, our UAV team – comprising a pilot and a surveyor - then flew our Vogel R3D system over the live railway. The flight was conducted from a position of safety in a designated green zone with a site warden attendance. No track access or possession was required.

The Vogel R3D system consists of an industry-leading UAV platform and 100-megapixel camera that enables us to take hundreds of overlapping high-resolution images that can be used to create a wide range of image and data-based deliverables. Two days were spent establishing the survey and UAV controls, with a further two days spent flying in order to capture the required imagery. With processing taking a further two weeks, the entire project took just four weeks to complete.