Automated Remote Monitoring of Avalanches Keeps Tracks Clear

Protecting the railroad against disruption caused by avalanches takes any number of forms, from physical infrastructure such as snow sheds, built of structural timber with concrete retaining walls that protect the track in the path of avalanches, to avalanche forecasters and wired slide fences. But what’s the latest thinking when it comes to applying digital technologies to this potentially costly issue, both in terms of customer inconvenience and operator reputation? 

L.B. Foster is one of the world’s leading suppliers of track products and friction management solutions. Following the company’s acquisition of UK mechanical, electrical and software engineering specialist The TEW Group, L.B. Foster is now applying the group’s extended capability in digital communications to remote condition monitoring (RCM) on the railroads. Peter Jones is Vice President of Global Technology. He says: “The enhanced skill sets that we now have within our business are opening up innovative new integrated solutions for our customers. We are looking at ways of applying our knowledge and experience in traditional mechanical and electrical engineering and creating smart interfaces with the latest in software and digital technologies to create intelligent, data-driven solutions.

“Working with a number of leading Class 1 freight railroad operators in the US and the transit network operators in the US and across Europe, we are creating a comprehensive suite of software and hardware solutions that deliver real-time data, CCTV images, SMS and email alerts to keep the railways moving. The applications range from flood and bridgestrike warnings to streamlining maintenance cycles by maintaining a watchful eye on fluid levels in trackside friction modifier dispensers. 

“A real success story is our Avalanche Total Track Monitoring. It’s an innovative piece of engineering that demonstrates how, as a business, we are joining up the skills from different parts of the company to produce new ways of doing things. Previously we could be accused of providing standalone products, but now we’re all about integrated solutions that add value to our customers’ businesses.”

Neil Roberts is L.B. Foster’s product manager for Total Track Monitoring. He says: “One of the main products installed in areas at risk of avalanche in North America is slide fences. Avalanches run into these systems from the slopes above, breaking wires strung between the poles, this alerts personnel who can quickly react by implementing trains at caution or imposing closures on the railway. But they are not infallible. Whilst they are designed to provide alerts against avalanches, they require a high level of maintenance through the winter due to ice breaking through them, wild animals breaking them, or the cables breaking on their own accord. Such events inevitably lead to false alarms, with expensive maintenance crews dispatched unnecessarily. Furthermore, slide fences can cost the railroad an awful lot of money to maintain.”

The issue of maintenance cost has encouraged a Class 1 railroad to look at alternative solutions, including wireless avalanche detection systems. This includes Avalanche Total Track Monitoring by L.B. Foster. The system is an end-to-end solution that sends alerts to operators about events in often remote locations that can lead to snow, trees and debris on the track. Proactively monitoring such events increases safety, minimises costs through a reduction in service delays, and enhances reputation resulting from guaranteed continuity of service provision. 

Avalanche Total Track Monitoring

Part of the company’s broader Total Track Monitoring capabilty, L.B. Foster’s Avalanche Total Track Monitoring solution applies innovations in mobile technology, CCTV, low energy and software to deliver a system that can be installed where fixed infrastructure is unavailable. The system uses long-life battery-powered RCM tilt and position sensors attached to vertical posts. When an avalanche occurs, the posts are knocked over triggering an alert that is automatically relayed to a control centre. The small, inexpensive sensors have the cost potential to be used over hundreds of miles of track susceptible to avalanche or mudslide events. 

Controllers are alerted when integral G-force accelerometer sensors installed on top of the system’s vertical posts are activated. The system is programmed so that the posts must go from being completely vertical to a 30-degree tilt within one second. If just one sensor is knocked over it will cause an alarm, but the system will not indicate there is an avalanche. However, if two sensors are knocked over, the system identifies that an avalanche has been detected and an alarm is sent to the control room. The railroad operator can then investigate the scene and react if the track is not passable. 

“By the nature of their often remote location, the railroad network has a lot of areas where communications can be challenging, plus and the locations generally do not have power,” adds Neil Roberts. “So with our avalanche monitoring solution we are building a number of different systems for them to use out in these hard to reach areas.”

That includes using L.B. Foster’s innovative solar gateway CCTV where power and data cables are unavailable. The self-powered system sends alerts and images via 3G communications for security or environmental events. When included as part of a comprehensive remote asset condition monitoring scheme, Solar Gateway CCTV is a fully integrated monitoring, recording and communication solution.

Test, 1-2

The United Kingdom has been using wireless technology for the past five to six years for flood detection and embankment monitoring. L.B Foster has taken this technology and applied it to predicting and calling avalanche events. 

Two test systems were trialled, one was fixed to a slide fence and another was placed in a snowfield where there was the potential for an avalanche. The system that sat next to the slide fence suddenly went into alarm mode in the Spring because the snow had melted and the poles had fallen over. The experiment simply consisted of pushing these sensors into the snow. 

A relay box with four tags on one system and three tags on another were set up. The tags were G-force accelerometers totally enclosed in a tube, sending a signal to a gateway every four minutes. If the gateway indicated that one of the tags had disappeared it would send a warning to the dispatcher. 

Wind was also an identified issue. Poles moving in the snow created their own hole around the bottom of the post. This caused false alarms to the system and was subsequently programmed out. The tags were then programmed to respond to movement from vertical to a 30 degree tilt in one second. 

However, every false alarm required maintenance crews to go out and investigate. Neil Roberts continues: “When we came to trial our MkII solution the response of our Class I partner was, ‘If we can remotely access the system to see what the situation is on-site, to look at the tags and see their orientation, to see signal strength, to see whether the battery level is up and what the temperature is, we don’t have to send people into a potentially dangerous environment.”

Currently, the system can cover a distance to the gateway of approximately 2,000 ft, but adjustments are being made to improve the wireless system. Tag orientation, signal strength, battery power and the current temperature are all displayed on a monitor. The MkII system consists of larger posts with a base and a shear pin in the back of it.

“The MkII has been installed for over six months and there have not been any false alarms,” said Roberts. “The system is now ready to go from a commercial point of view and from a product safety point of view as well.”

Along with rewriting the sensor algorithms so that wind vibration triggering is eliminated, a ‘shock factor’ was added which gives a velocity indication depending on the speed of impact. A status check has also been modified to delay a maintenance alarm in the event of any temporary radio loss or interference.

Predicting over a bigger area

Future development of the system include the creation of a repeater system to allow the scanning to spread out for miles instead of the system’s current range of around 2,000 ft. The existing system is capable of taking three or four gateways, each carrying about 20 tags. Working with a repeater system would allow for many more tags and miles of coverage area. 

Each of the tags come with a temperature reading, so currently researchers are logging that data and creating trends. The goal is to be able to predict an avalanche or a landslide before they happen. So, for example, if there is a 5-degree rise in temperature in a 24- to 48-hour window that could be a potential risk and an alarm would be sent to dispatch. 

“Currently we are in the area of not being able to accurately predict these events because right now the slide fences that are out there are reactive not predictive,” said Roberts.

Another example is when an area is experiencing heavy rainfall and the railroad knows there could be some slopes under pressure. The system could be deployed rather quickly in the sensitive area and could then communicate if a mudslide did happen so the railroad company could react accordingly.

LIDAR

A North American Class 1 railroad is currently working with L.B. Foster Total Track Monitoring on field trials using L.B. Foster’s Insight LIDAR (Light Detection and Ranging) technology for rockfall detection in the High Country.

Dr Mark Aston is L.B. Foster Europe’s Chief Technical Officer. He explains about the challenge of safeguarding against rock debris on the line: “Conventional rockfall monitors use wires across the top of the track that break when a rock falls through them. The problem with this technology is that it does not indicate if the rock has ended up on the track or rolled off, plus it requires engineers to re-string the monitors each time they break.

“The L.B. Foster’s Insight LIDAR used in the UK for level crossing safety are now being trialled in use on the rail itself. If a rock of sufficient size to pose a threat to a train is detected on the track, Insight LIDAR technology remotely alerts controllers about the size and location of the obstruction, without an engineer ever needing to visit site and re-string a wire detector. The rockfall LIDAR can monitor hundreds of miles of cuttings and rock faces adjacent to train lines.”

Avalanche Total Track Monitoring by L.B. Foster is part of the company’s comprehensive suite of RCM solutions for a wide range of events. These include flood, temperature, level crossing safety, rockfall, mud and landslide. All solutions incorporate remote monitoring capabilities with control centre alerts and data management software.

For further information on avalanche monitoring or to discuss remote condition monitoring, please contact Neil Roberts nroberts@lbfoster.com.

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Editors notes

LB Foster delivers world-class engineering solutions in rail, energy and industrial automation. What we do keeps our world moving.