As part of a major restoration project to secure the future of the Ribblehead viaduct, laser scanners and drones have been used to map every inch of the iconic structure.
North Yorkshire’s most recognisable railway icon was 3D scanned and turned into a computer model by surveyors as part of a £2.1 million project to upgrade to brickwork and drainage.
This detailed digital recreation of the 144-year-old structure, which carries the historic Settle to Carlisle railway 400 metres across the Ribble valley, will help engineers make repairs now and closely monitor areas needing any further attention in the future.
Network Rail’s North West route director Phil James said: “We’re always looking to innovate on the railway and seeing drones and lasers being used to care for such an historic structure is really impressive.
“I was at Ribblehead viaduct when we started work a week ago and saw for myself the huge scaffolding platforms now in place so my team can improve brickwork, mortar and drainage. Great care and attention is going in to make sure our work is right from a heritage perspective.
“This digital model plays a major role in that as we secure the Grade II listed-structure’s future for passengers and tourists as part of the Great North Rail Project.”
Commendium carried out the LiDAR survey, in conjunction with heritage consultancy firm Wardell Armstrong. At 402 metres long and 32 metres high, the 24-arch Ribblehead viaduct is the largest man-made structure the company has ever scanned.
In a LiDAR scan, light is emitted from a rapidly firing laser. This light travels to the ground and reflects off of objects such as buildings and tree branches. The reflected light energy then returns to the LiDAR sensor where the is recorded and is then used to build up the 3D computer model.
Over 100 separate scans were taken from locations underneath and on top of the viaduct.
In addition, drone flights took high-definition photographs of the Grade II listed structure. The data gathered was then used to build up the 3D computer model by Network Rail’s specialist computer aided design (CAD) team.
Commendium chief executive Richard Walters commented said: “We have all known and loved this location for most of our lives, it is even part of our childrens’ cultural awareness with them learning songs about it at school. So to survey it has been a privilege.
“The resulting LiDAR scan not only shows areas which need repair, but also areas where water could damage the stonework in the future, so leading to other preservation works.”
The maintenance work on Ribblehead viaduct, which is due to be complete in February 2021 and is not expected to cause any disruption to rail passengers, includes:
- Brickwork repairs;
- Removal of vegetation and repairing the damage caused by plants and weeds;
- Upgrades to drainage across the viaduct’s 24 arches;
- Repainting metal and pipework.