Railways in the time of climate change

A site investigation is currently underway, but an interim report, published by Network Rail to assess the current controls and management of miles of railway, recollects that heavy rainfall during one of the wettest Augusts ever recorded in Scotland had disrupted railways and other transport modes.

That morning, weather records indicated thunderstorms and over 50mm of rain in the Carmont area between 05:00 and 09:00 am. Water flowing from higher land beside the railway washed stone onto the track after another train had passed on the same line two and a half hours before.

Transport Secretary Grant Shapps later said they owed it to those who died or were injured in the incident to "learn and act on every possible lesson to ensure this is never repeated."

If anything can be learned from this tragedy, it is that a strong link between infrastructural damages and climate exists. In fact, Network Rail admitted that the response to extreme weather must be improved.

“Climate change considerations are being embedded in our standards and planning, and the Government’s Committee on Climate Change recognises our resilience planning for climate change adaptation is well advanced,” the report reads. “But it is clear from the impact of severe weather events experienced in recent years that this is an area that is accelerating faster than our assumptions, and as a result it has become even more important to implement these plans.”

So what can be done to be better prepared in the future?

A study by Nikola Bešinović of Delft University of Technology (in the Netherlands) about resilience in railway transport systems, shows that “To obtain more accurate resilience assessment, system-based metrics are required to capture effects on transport services and transport demand,” Bešinović wrote.

“In particular, demand-centered resilience metrics shall be needed to precisely capture impacts on users of transport systems. Meanwhile, topological measures are more straight-forward to apply as they need less data, but also tend to provide limited information about the system.”

Bešinović concluded that although approaches for resilience in railways remain mostly unexplored it is becoming “more and more important with increased needs for transport and future mobility on one side and climate changes on the other”. For instance, he expects an increase of new methodologies and data-driven analysis to address adaptation in railway transport systems.

At least for Western countries, the Stonehaven derailment sounded like an alarm bell and a sober reminder that work needs to go further and quicker to keep up with the frequency and severity of weather events.

“Climate change is often viewed as a future problem,” says Lisa Constable, Network Rail’s weather resilience and climate change adaptation strategy manager. “However, it is already causing more frequent and more severe extreme weather events which can have a significant impact on our infrastructure, specifically our earthworks (cuttings and embankments) and drainage systems.”

In their 2019 Progress Report, the Government’s Committee on Climate Change said that Network Rail’s resilience planning for climate change is well advanced and that the railway remains one of the safest in Europe. To maintain this status, the company has some plans in place.

The Weather Resilience and Climate Change Adaptation Strategy has been in place since 2017, and was recently followed by a new Environmental Sustainability Strategy that outlines adaptation ambitions and a roadmap to 2050.

They established that resilience should be key when railway assets are designed, built, operated, maintained and replaced. “Our mantra for replacing assets in the future will be ‘replace like with better’ rather than ‘replace like for like’,” Constable adds. “This change will mean we will continually improve the network, making it more resilient for our customers and passengers.”

The network’s investment in earthworks and drainage portfolio has doubled over the last 10 years and they plan to spend an additional £1.3bn by 2024 to improve the management. From the record £53bn allocated by the Department for Transport, they will fund the sustainability strategy. They also launched an independent task force led by Dame Julia Slingo to assess the way climate change is dealt with.

As trains already are a green form of mass transport, a new trend, more attentive to sustainability, should be established when it comes to building transport infrastructure.

“This is no time to rest on our laurels, so over the next few years we want to support the Government’s target of net-zero carbon by 2050,” Constable says. “Specifically, this means running a low-emission railway, providing a reliable service to passengers that is resilient to climate change, improving biodiversity across our network and ensuring a sustainable use of materials with minimal waste. We are already making good progress in rolling out energy efficiency measures across our estate and our project teams are starting to embed an understanding of carbon impacts in our infrastructure and engineering works.”

“The environmental sustainability agenda is becoming increasingly important in the face of challenges posed by climate change – not just on the railway or in transport but across the world” she concludes. “There has never been a more important time for everyone to think about what can be done to support Britain’s green economic recovery from the coronavirus pandemic.”

Image: Richard Fox Pix.