Climate change is here. And the higher temperatures, more frequent heatwaves, heavy rainfall, intense storms and coastal erosion it brings are impacting our infrastructure more and more. At SNCF Group as a whole and at infrastructure manager SNCF Réseau in particular, this is the new reality—and one our teams have already factored into their work. Our aim: ensure the network’s long-term future, maintain service quality for passengers, and create a resilient infrastructure system.

We take a closer look with Benoit Chevalier, Corinne Roecklin and Yann Freson, experts in adapting to climate change at SNCF Réseau.

Benoit Chevalier: We began with the estimates used to plot the climate change adaptation trajectory published by the French Ministry for Ecology. These point to a 4-degree rise in global temperatures by the end of this century, and probably more in Europe. We now know that resulting climate change will lead to more heatwaves, more adverse weather and, over the long term, rising sea levels.

So, can we keep our passengers travelling seamlessly in a world where bad weather caused by the sun or water cycle is on the rise? We need to take the bull by the horns—get to grips with it, and invest to guarantee our network’s long-term future. And to do that, we’re drawing on our years of experience managing a network that has always been exposed to bad weather.

Benoit Chevalier: Correct. And all SNCF Group companies, in particular SNCF Réseau and, on the passenger side, the Rolling Stock Division, are working on it. In fact, all major industrial groups face the same challenge and investments, because climate change is going to affect all of us. We’re all in the same boat, and we’re all adapting our structures and resources to meet the challenge.

Corinne Roecklin: We’re already seeing the impact in summer heatwaves and overall rainfall, plus operational challenges like the rampant growth in trackside vegetation.

Looking forward, we don’t know all of the potential fallout. For example, what happens to our physical infrastructure when intense rainfall is the norm? We can calculate the temperature of a rail exposed to baking sun, but there’s no mathematical formula that can predict what happens to an embankment subject to repeated flooding. We also need to think about how climate change—and heatwaves in particular—will affect our employees. We simply don’t have all the answers yet. Even the IPCC (Intergovernmental Panel on Climate Change) doesn't know, but we’re all studying it very closely.

Benoit Chevalier: Managing assets effectively is fundamental in our business, so adapting to climate change is already ingrained in us. For example, we’re developing increasingly effective tracking systems such as Toutatis, which we use to monitor the condition of our earthworks during heavy rain. Digital tools, new standards—we’re constantly adapting.

Yann Freson: We’ve set up a “merit system” to rank measures from least to most effective, based on their technical feasibility and cost. Take network regeneration: when we replace old components with new, we have to incorporate new specifications that factor in climate change. It’s a virtuous solution because it makes our network more resilient, so it’s the highest-ranked, most “merit-worthy” solution. A good example is the new ERTMS signalling on some lines: it’s much less vulnerable than prior systems, since it relies on data processing centres in air-conditioned facilities, so fewer resources are physically exposed out on the tracks. That’s how regeneration can make the network more resilient. But depending on the type and nature of the resources, regeneration might not be enough.

Concretely, an IT component is regenerated every 20 years or so, and adapted gradually over time to climate change to guarantee that it will never fail because of global warming. But earthworks are another matter: there’s no renewal date and no actual regeneration cycle. Instead, we have to focus on regular maintenance.

Benoit Chevalier: Yes, even though such equipment is more expensive, since it requires more robust design and has to be built to more demanding specifications. For example, on one of our pilot lines we’ve deployed a 1500-volt CS2R catenary (which stands for simplified reinforced standardized catenary). It’s designed to avoid heat-related detachment, a problem that requires lots of repairs. But it’s not suitable for all situations. And in some cases, we opt for specific one-off measures, or redundancy or maintenance, until components can be regenerated. That’s a technical or budgetary workaround that lets us temporarily extend the life of an asset that we know will need to be regenerated at some point to cope with climate change.

Yann Freson: Here’s one: making little-used lines perfectly resilient is not a priority. It’s an issue we raise and discuss, case by case, with our regional partners. But sometimes we do have to make a special effort to regenerate a section earlier than planned. These are cases where retrofitting an existing installation is the least “merit-worthy”, i.e., makes the least sense from an economic point of view, but we jump in all the same to upgrade a vulnerable track segment or replace a section that’s been damaged by a severe weather event.

Yann Freson: Yes, ranging from the most evident and “merit-worthy” measure to the least “merit-worthy” one, when we have no real choice. We use this range of options to plan the most effective pathway. This helps us weigh up choices and decide which works best in each situation, for each resource and risk, while continuing to innovate to add new options to our portfolio of solutions.

When we can, we’ll use a cost-benefit analysis and go for the most virtuous, i.e., top-ranked solution, but if we can’t, we agree to sacrifice some service quality or budget constraints. When we build a new line, we face climate adaptation options, too. And once again we make a choice: we want our new lines to be resilient and we want to offer top-notch service, which means we try to include climate change in the mix from the design stage, while respecting the budget as far as we can.

Benoit Chevalier: As closely as possible, yes, because you can often deal most effectively with hazards at a local level. As infrastructure managers, we’re dutybound to protect our own operations, but we also need to work as closely as we can with local players. That’s particularly true face with flooding or wildfires, as in the south of France, or when we interact with farmers to handle run-off. We try to collaborate with all local initiatives that take a collective approach to solving issues. Getting everyone on the same page advances our interests and those of the regions we serve.

Benoit Chevalier:  Adapting to climate change impacts each of our business lines, and designing resilient resources is part of what SNCF engineers do every day.

Instead of creating a team dedicated solely to climate change, we opted to set up a network of relay points to spread the word Group-wide. This is also a good way to avoid the temptation of launching massive—and polluting—works on the network. We need to adapt, but by finding virtuous solutions, meeting other challenges—doubling rail’s share of total transport, for example—and reducing our impact on the environment. Which means continuing to invest in a more robust, resilient, and higher-capacity network. We’re pressing ahead in all of these areas.