Rail is a vital component of transportation infrastructure, facilitating the movement of passengers and freight across vast distances with low climate impact. However, railways and railroads are often vulnerable to natural hazards such as rockfalls and landslides, which can pose significant risks to both human safety and the environment. As climate change intensifies weather patterns and geological instability, the need for effective monitoring and early warning systems has never been more critical.
The Risks of Rockfalls and Landslides
Rockfalls and landslides can occur suddenly and with little to no warning, particularly in steep terrain where railways must follow geographic contours. These events can, at best, lead to the obstruction of tracks and at worst derailments, catastrophic accidents, death and destruction. For passenger trains, the human consequences can be dire, resulting in large numbers of injuries or fatalities. Even where physical injuries may heal, the psychological impact on survivors can be profound, leading to long-lasting trauma.
Freight trains face similar risks carring many things including potentially dangerous bulk materials such as chemicals, fuels, and other hazardous goods. A derailment caused by even a small landslide can lead to spills, fires, or explosions, posing a threat not only to the train crew and passengers but also to nearby communities and ecosystems. The potential for environmental contamination and the costs associated with cleanup and recovery can be staggering with recent high profile disasters incurring costs in the hundreds of millions of dollars.
As climates change, extreme weather events are observed to become more frequent and more severe. This increased intensity of infrastructure stress boosts the likelihood of destabilising both slopes and rock formations. Global railways are already reporting an uptick in weather related infrastructure failures including earthworks and embankment failures with no slow-down predicted.
This rockfall in Europe was detected by fiber optic sensing
The Role of Fiber Optic Sensing
To mitigate these increased infrastructure risks, railway operators are increasingly turning to technology to help mitigate the increasing threats. One such technology is fiber optic sensing which is used to monitor failures of slopes and rockfalls in real-time along long route distances. Optical fibers running alongside the track, below ground level, can detect ground vibrations such as those generated by a rockfall or a landslide. This sensing technique is called Distributed Acoustic Sensing, (you can see how it works here). This realtime vibration monitoring can provide critical information alerts for rail operations teams to alert them to potential hazards before train traffic reaches the affected location. The alert information provided helps prevent natural hazards escalating into rail disasters.
One of the key advantages of fiber optic sensing is its ability to cover large areas with minimal on-track infrastructure. Unlike traditional monitoring methods, which rely on many individual point sensors detecting their immediate surroundings, distributed acoustic sensing relies on just a single optical fiber to continuously gather data over extensive distances (tens of miles/kilometres). This capability allows for the real-time detection of ground movements, enabling railway operators to take steps to ensure safety of their trains. These methods might be applying speed limits or driving to line of sight over the affected location, or dispatching people or even drones to inspect in advance of scheduled traffic to assess the severity. The vital aspect is that incidents and their locations are known about before a train encounters them at speed.
Enhancing Safety, Security and More
Implementing fiber optic sensing technology not only enhances safety through detecting rockfall and landslide events but can also improve rail security too, through detection of people and activities near the track, (see more applications of the technology here). By providing real-time security data operational risks and costs such as theft and tampering can also be reduced. Using the extended monitoring data helps rail operators and maintainers to make informed decisions about their infrastructure, reducing downtime and minimising disruptions to service. This proactive approach can lead to significant cost savings.
Conclusion
As the frequency and intensity of rockfalls and landslides increase due to climate change, the railway industry must respond by the implementation of advanced monitoring technologies like fiber optic sensing. By investing in these innovative solutions, railway operators can enhance safety for passengers and mitigate the risks associated with transporting hazardous materials. Ultimately, the adoption of such technologies will not only protect lives but also ensure the continued reliability and resilience of railway operations in the face of both natural and man-made threats.
