The increasing impact of heavy rainfall on railways

With multiple railways hit by flooding in the past weeks, it becomes more and more visible that extreme rainfall can have a devastating impact on railway infrastructure. What are rail infrastructure managers doing to prepare for this type of more extreme weather?

Weather extremes are intensifying with global warming warming, including large amounts of rainfall in a short period of time. This can lead to great damages in rail infrastructure, and of course to a halt train operations, such as recently in Norway and just this week in Austria.

According to the International Union of Railways (UIC), heavy rain and consequent flooding may impact infrastructure by washing away ballast, leading to failure in points and signalling equipment, as they rely on intricate wiring and power supplies. It can also cause delays as trains must reduce their speed to avoid damage if the water level rises above the rails, overwhelm the drainage systems on the railway and cause landslides due to excess run-off.

‘Big room for improvement in resilience’
“Both infrastructure and operation still have big room for improvement regarding railway resilience and extreme climate events preparedness”, says Jesús Palma, who works at the International Union of Railways (UIC) in a project on making railways resilient to heavy rain.

The UIC initiated a set of five projects under the name of Resilient Railways Facing Climate Change (RERA), including RERA-Rain, studying the risk of heavy rains, which started in April 2022. In the project, one of the goals is for the participating rail infrastructure managers, which include the likes of DB, ADIF and Network Rail, is to exchange knowledge and experience, the project manager explains to RailTech. “Resilience is not a standardised aspect and has no regulation concerning it. During our meetings, we have been able to spot that there are some countries in which, when heavy rain occurs, trains are slowed or traffic is even interrupted. Commonly, there is no definition of what heavy rain is and so, there are no thresholds that help the operators to make decisions.”

So, one of the goals is for the different administrators to learn from other ones’ experience from the forecasting phase until (if necessary) applying corrective measures, and to be able to set thresholds which help them in their decision-making processes. Exchanging knowledge and experience of which have been the applied solutions for different extreme events could increase the response preparedness of the different railway administrators.

The weak points when heavy rain hits
“Regarding infrastructure, one of the weak points we have been able to spot is drainage systems maintenance, among many others. From the operation side, prevention using weather forecasting tools and weather alerts management systems to protect operation from intense rainfall events”, says Palma about the project.

With the help of accurate weather forecasting tools, the preparedness of the line against an extreme rain event can be increased through specific drainage maintenance campaigns in critical points, he explains. Concerning operation, accurate forecasting and the existence of protocols would also be useful to provide accurate real-time passenger information.

Belgium is one of the countries that dealt with flooding after large amounts of rain back in summer 2021. An Infrabel civil engineer called it “the worst disaster we ever experienced on the Belgian railways”, and RailTech contacted Infrabel again to ask how it is preparing now for future extreme weather.

The deadly flooding in Wallonia claimed 39 lives. It also caused extensive damage to railway infrastructure: 100,000 tonnes of ballast were washed away, and 4 bridges and several kilometres of track were destroyed. “This painful episode in Belgium’s history is one of the consequences of climate change. Six months later, storm Eunice swept across Belgium, causing a series of incidents. These extreme climatic phenomena have prompted Infrabel to consider how the infrastructure manager should adapt to this new reality”, says an Infrabel spokesperson.

To prepare for extreme weather, Infrabel and operator SNCB have also introduced “hot weather”, “autumn” and “winter” plans, which include preventive measures to avoid the impact of certain climatic hazards on rail traffic. For example, Infrabel has invested in improved ventilation in signal boxes to prevent the installations from overheating. In 2022, they also developed an “intelligent” switch heating system, i.e. controlled by meteorological data.

For the longer term, Infrabel is preparing an in-depth analysis of the exposure of its assets to the impacts of climate change. The priority analysis concerns the stability of embankment track embankments in the event of flooding and heavy rain. In doing so, Infrabel will map vulnerable areas, taking into account long-term climate scenarios.

Monitoring for more resilient rails
The Belgian railway manager is also studying the contribution of the Internet of Things (IoT) to the strategy for adapting to climate change and monitor the condition of assets. “For example, at the exit of the Diabolo tunnel used by passengers travelling from Antwerp to Brussels Airport, there is a reservoir, coupled to 3 huge pumps, responsible for channelling rainwater back into the drainage system. However, extreme rainfall has highlighted the need to be aware of potential anomalies. A malfunction of these pumps could cause water to rise at the tunnel exit, with consequences for traffic, and even damage to other parts of the infrastructure. These pumps are now equipped with a “watchdog,” connected box constantly monitors their correct operation and is able to reveal any faults that might indicate a breakdown. “This ensures that when you need to rely on it at all costs, the pumping system will be fully functional”, says the spokesperson of Infrabel.

Not far away, a second connected object, independent but complementary to the first, is also set to play a crucial role. Connected to a probe buried in the ground, it informs the technical teams of the degree of hygrometry of the soil, and therefore its capacity to absorb – or not if it is already waterlogged – heavy rainfall. This information is decisive in determining the more or less critical role that the pumps will have to play. This warning system has also been designed for wind, according to the Belgian infrastructure manager.

Jesús Palma of the UIC sees that infrastructure managers and operators are day by day more experienced concerning resilience: “The economic resources are not always enough, but they are conscious about the problem of climate change and they are willing to allocate the necessary resources for that purpose. The question is having criteria to optimise and prioritise the available resources, and that is the point in which the RERA project aims to offer recommendations and methodology”.

Kehinde Olusegun

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