Infrastructure: Embracing nature can enhance rail’s soft resilience

The International Union of Railways is urging more railways to adopt Nature-based Solutions as a means to enhance the resilience of infrastructure in an era when both the natural world and man-made assets are under severe pressure from climate change.

As we look for innovative and cost-effective techniques to build safer and more reliable railway systems, could we learn something from nature? With increasing impacts on the safety and operations of our railways from extreme weather events, from washouts and landslides induced by intense rain to overheating passengers in stations during heat waves, we need to ‘harden’ our system.

We need to strengthen the infrastructure, buildings and trains to failure, making them more resilient and able to withstand environmental hazards. Yet there are also means by which we could strengthen the system with ‘soft resilience’ too. UIC published its latest work on climate change adaptation in March this year, entitled REsilient RAilways or RERA, focusing on the two main hazards to rail: heat and floods.

RERA Rain focuses on the impact of extreme precipitation on railway infrastructure and operations, providing an overview of how heavy rainfall affects embankment stability, drainage systems and service disruption, while highlighting innovative monitoring and adaptation practices used by UIC members.

RERA Temp examines the challenges of rising temperatures and heat extremes, analysing effects on track stability, overhead line systems, staff and passenger comfort.

Both reports outline a structured resilience framework for railways, focusing on risk monitoring, impact thresholds, criticality assessment, infrastructure adaptation and continuous learning. This framework is intended to help railways to manage the growing challenges of extreme rainfall and heat. One key finding has been the huge potential for using soft engineering and natural solutions both for cooling and water management.

The railways still have very little experience of using Nature-based Solutions (Panel), but it seems that they could be a very beneficial way to improve infrastructure resilience, protect biodiversity and contribute to net-zero goals — all while delivering cost-effective, long-term results. The question is how best to deploy them.

What’s nature got to do with it?

Nature is in crisis, with humans’ use of land, resources exploitation and climate change as main sources of biodiversity loss.

According to global environmental charity WWF and the UN-backed Intergovernmental Science-Policy Platform on Biodiversity & Ecosystem Services, wildlife populations have dropped by 69% since 1970, and more than 32 million ha of forest were lost between 2010 and 2015. Transport infrastructure, including railways, contributed to this decline — but rail can also be part of the remediation process.

As the most sustainable motorised mode, railways can double as ecological corridors, reconnecting habitats, boosting biodiversity and supporting conservation at scale. That’s where the EU-funded Symbiosis project comes in. Co-ordinated by UIC, the project is mapping climate risks for rail infrastructure across Europe, evaluating the exposure and vulnerability of railway and energy networks to different climate-related hazards, where nature-based interventions can make the biggest impact by providing biodiversity co-benefits and further enhance the provision of ecosystem services.

Moreover, Symbiosis is also building a catalogue of Nature-based Solutions applicable in the design and management of ecological assets, together with a set of guidelines for decision makers and transport designers for integrating these NbS into infrastructure planning and asset lifecycle management.

Several examples of NbS are already being trialled in the rail sector:

• restoring wetlands or river improvements in the wider catchment to absorb floodwaters near vulnerable tracks;
• planting deep-rooted vegetation on slopes to prevent landslides;
• adding green roofs and planted corridors to reduce heat at stations and critical lineside equipment vulnerable to heat;
• using climate resilient landscaping to create buffer zones for better drainage and biodiversity.

However, it is legitimate to ask if these interventions are any better than the traditional approaches to cooling, draining or embankment stabilisation. Railways span thousands of kilometres, often crossing floodplains, forests, and coastlines. Grey infrastructure is tried and tested, but it is also rigid, expensive, and often requires significant amounts of maintenance. NbS, on the other hand, offer a dynamic, self-regenerating layer of protection that can reduce maintenance costs, as well as enhancing climate resilience. This approach can help our targets on biodiversity enhancement and create a much more attractive railway environment.

Case studies

Fortunately, we are now seeing tangible deployment of NbS methods on railways around the world. UK infrastructure manager Network Rail has worked with Leeds City Council and environmental charity Aire Rivers Trust to increase the resilience of the railway around the city. The partners are planting up to 2 million trees and new hedgerows by Kirkstall Bridge in Leeds as part of a flood alleviation scheme. Kirkstall Bridge had previously been particularly vulnerable to flooding, causing regular disruption to trains throughout the region. By aerating the soil along with the roots of the trees and shrubs the land will better absorb water and therefore reduce the risk of flooding.

In the USA, Class I railroad Norfolk Southern has installed a ‘Living Shoreline’ at Lamberts Point in Norfolk, Virginia, a key marine terminal for intermodal freight operations. The site faces flood risks due to erosion at the Elizabeth River shoreline. As part of efforts to mitigate this risk, NS has collaborated with the Elizabeth River Project to create a sustainable living shoreline using sand, marsh plantings, stone and oysters. This project provided flood protection, benefiting the railroad, environment, local community, and businesses.

Thirdly, in its role as Austrian infrastructure manager, ÖBB implemented a large-scale river restoration project during the ongoing construction of the Koralmbahn, a fast line being built between Graz and Klagenfurt. The project, along with other interventions along the corridor, is expected to reduce Wien to Klagenfurt journey times by more than an hour when it is completed in the next few years.

The River Lavant, previously confined to an artificial channel, posed a flooding risk to the new line and a nearby station. To address this, ÖBB restored 1∙4 km of natural river course and created multiple connected wetland habitats across a 20 ha area. These wetlands now act as flood retention zones, improving protection for the railway infrastructure. The project also removed artificial barriers, enhancing the river’s ecological connectivity.

One year after completion, the restored area successfully withstood a minor flooding event with no damage to railway assets. As a co-benefit, biodiversity has improved, and the area now supports returning species, offers public access via a cycle path and nature trail, and contributes to local recreation and tourism.

Ensuring uptake of NbS

To embrace more Nature-based Solutions, railways need to shift mindsets, align policies, and invest in practices that integrate environmental systems into infrastructure planning. This is unlikely to happen overnight, but change is already under way with some key enabling measures now being widely recommended:

1. Embed NbS in Strategy & Policy: include NbS in climate adaptation and asset management strategies, treating green infrastructure as essential.
2. Value Ecosystem Services: incorporate the long-term benefits of nature — like flood mitigation, cooling, and erosion control — into business cases and cost–benefit analyses.
3. Build Cross-Disciplinary Teams: encourage collaboration between engineers, ecologists, landscape designers and local communities to identify nature-compatible interventions.
4. Map Risk & Opportunity: use geospatial tools and vulnerability assessments to identify where NbS — such as reforestation, wetlands, and slope planting — can best support resilience.
5. Adjust Standards & Procurement: adapt infrastructure specifications and procurement frameworks to allow for green measures alongside grey infrastructure.
6. Pilot, Monitor & Scale: start with demonstration sites or hybrid approaches, monitor outcomes and share data to build confidence and refine methods.
7. Engage Stakeholders & Communities: co-develop NbS with landowners, environmental agencies and communities to ensure the measures proposed are context-sensitive and supported.

By recognising nature as a rail asset just like tracks or signals, railway holdings and infrastructure managers can unlock co-benefits for resilience, sustainability, and biodiversity.

Acorn and EU-Symbiosis

Two initiatives are now emerging to ensure NbS uptake makes progress in the years to come.

Acorn — the Alliance for Connecting Railways & Restoring Nature — is UIC’s long-term initiative to drive adoption of nature-positive action across the global rail sector. It provides a structured, collaborative platform for members to deliver ecological outcomes while staying aligned with evolving policy and regulatory frameworks. Acorn acts as a central ecosystem for knowledge exchange, technical guidance and innovation. By uniting railways globally, Acorn helps embed ecological value into core railway planning and operations.

Complementing this vision, the EU-funded Symbiosis project is advancing tools and strategies to integrate biodiversity into infrastructure planning and delivery. It covers key areas such as harmonised biodiversity data collection, procurement criteria, cross-cutting policy alignment, and a new lifecycle-based tool to assess carbon emissions, mitigation potential and biodiversity impacts of infrastructure projects.

Together, Acorn and Symbiosis are catalysing a shift from reactive mitigation to proactive ecological value creation. By connecting global rail actors and building practical tools for implementation, they are helping railways transition from environmental compliance to ecosystem regeneration, turning tracks and corridors into pathways for nature recovery.

*Lucie Anderton is Sustainability Director and Lorenzo Franzoni is Biodiversity Lead at the International Union of Railways.

This article first appeared in the October 2025 issue of Railway Gazette International