Network Rail’s Air Operations team has been testing a powerful new camera system that combines high-resolution photography with laser surveys and near-infrared images to give engineers an incredible view of the network.
The Multi-Angle Camera System – MACS – fits in a pod under the company’s Twin Squirrel helicopter*, which can cover many miles of railway in a single shift, carrying a pilot and aerial surveyor.
Network Rail’s test track near Nottingham, called the Rail Innovation and Development Centre, Melton, has been the test-bed for the system, with the helicopter flying multiple missions along the 13-mile route to give its engineers a detailed view of the route. A recent landslip – fully repaired – shows that the track has the same challenges as the public railway.
The MACS onboard laser creates a “point cloud” of up to 300 points per square metre, which can be used to build a 3D model of the railway, right down to overhead wires, bridges and more.
Meanwhile three 150 megapixel RGB cameras facing forward, sideways and straight down (nadir) take images, which are geometrically corrected (orthorectified) to make them useful for engineering purposes, while a fourth takes near-infrared images – which can be used to determine plant and tree health.
All these images are linked through an inertial measurement unit to provide accurate location data.
The system can also provide digital terrain maps without trees or buildings to help geotechnical engineers to “see” the railway clearly and understand the nature of any failures and even take action before a failure.
Sean Leahy, from Network Rail Air Ops, said: “Passengers and freight customers deserve a reliable railway and the best way to provide that is to know as much about our network as we can, to spot problems before they happen and maintain it to the highest standards. We have brilliant colleagues who are able to work wonders but they can’t be everywhere on the 20,000 miles of track we look after. The MACS is one of the ways we can help them by giving them the best data we can.”
Bradley Sparkes, of Network Rail’s Technical Authority team said: “We operate one of the busiest railways in the world, with over seven million train movements per year making traditional boots-on-ballast inspections a real challenge. When we do ultimately decide to send an engineer on-site for a closer inspection, we need to be sure we’re basing such a deployment on comprehensive and robust prior intelligence. This will help to drive a reduction in inspection related emissions, improvements in worker safety and enhanced asset intelligence.”
Data from the MACS will provide a solid foundation on which machine learning algorithms for an array of disciplines could be trained. This will help path the way for the utilisation of survey-grade drones, which will be able to fly increasingly long distances as Beyond Visual Line of Sight (BVLOS) capabilities mature.
The MACS will be offered to Network Rail regions for their use as part of the suite of equipment that can be carried by the helicopter, from thermal imagine to standard cameras.
*Network Rail’s Eurocopter (latterly Airbus Helicopters) twin squirrel G-NLDR is operated for the company by PDG helicopters of Cumbernauld.