UAS Use in Railway Inspections

Inspection of railroad track systems and right-of-ways has been a prime objective for commercial UAS. Burlington Northern and Santa Fe (BNSF) railroad is one of the FAA’s original Pathfinder program companies, working to test beyond-line-of-sight technology, training, and safety. In the October 2016 volume of Inside Unmanned Systems, Renee Knight profiled the use of UAS in rail inspection and maintenance. BNSF maintains 32,000 miles of track in the Western U.S., and uses a variety of inspection tools and techniques. The three primary structures that are routinely inspected are the ballast structure that supports the rails and ensures proper water drainage, bridges, and the rails themselves. The ballast structure is inspected using penetrating radar, while bridges are normally inspected by crews in lifts or cherry pickers. Rail integrity is normally checked by vehicle or on foot. However, a UAS can accomplish all of these tasks remotely, without putting a human in harm’s way, and without requiring the shut-down of a rail section. UAS increase fidelity of bridge inspections by providing a visual reference over time that can show changes in the structure. Ultimately, detailed inspections do not get better than the human eye, but where routine inspections are required, UAS provide an advantage by being quick to deploy and safe for the human crews.

UAS can also be used by rail crews and emergency responders in the event of an accident, by using thermal cameras to scan the cars that require the greatest amount of cooling. Additionally, if a freight train needs to stop because of an issue, the crew must check the length of the train – which could reach up to more than a mile and a half. Utilizing a small UAS to conduct a visual inspection of the train’s condition would save valuable time.

A current limitation of UAS (outside of regulatory line-of-sight rules) is the relatively short range of common multi-rotor aircraft, which are typically battery-powered. High-end commercial models may reach up to 30 minutes of battery life. In comparison, a manned helicopter carrying an infrared camera, near-IR camera, and stabilized zoom camera can cover hundreds of miles in a day, albeit at great cost of fuel and crew (Rail Engineer, 2011).

Testing beyond-line-of-sight flights to improve U.S. regulations is already underway, with railway inspections being one of the key industries to benefit from UAS. We can definitely expect to see regular use of UAS in the rail industry very soon, which benefits the industry at large with lessons learned and new technology developments.

References:

Knight, R. (2016, October). Flying the rails. Inside Unmanned Systems, Oct-Nov 2016. Retrieved from http://insideunmannedsystems.com/flying-the-rails/

Rail Engineer. (2011, July). Bird’s eye view from Network Rail’s helicopter. Retrieved from http://www.railengineer.uk/2011/07/08/birds-eye-view-from-network-rails-helicopter/