Building railway transport resilience to Alpine hazards in Austria

The harsh mountainous nature of the Eastern Alps, in which around 65% of the national territory of Austria is situated, poses a particular challenge to railway transport planning and management. Relief and steep slopes limit the space usable for permanent settlements and infrastructure. Hence, railway lines often follow floodplains or are located along steep slopes, which considerably exposes them to flooding and in particular to alpine hazards, e.g. debris flows, rock falls, avalanches or landslides. As a result, railway infrastructure and operation has been repeatedly impacted by alpine hazards. For instance, the major flooding in September 2024 led to undermined tracks, flooded tunnels and railway stations on Austrian East-west rail tracks in Lower Austria. The extreme storms of these days also left traces of devastation in the Austrian rail infrastructure. The direct financial damage was approximately up to 'EUR 100 million.

The indirect losses were even higher. Under normal conditions, on the entire Western route between Vienna and St. Pölten, usually around 550 passenger and freight trains  operate. When the extreme event caused the interruption of the western route, only around 150 trains were able to run daily.

The majority of alpine hazards are triggered by extreme/severe (hydro-) meteorological conditions such as heavy precipitation, rapid snow melt or extreme temperatures. Heavy rainfall events in Austria are significantly increasing due to climate change, with hourly rainfall amounts now being 15% higher than in 1980 (Haslinger et all, 2025). In the future, the risk from Alpine hazards could increase due to the impact of climate change. For instance, the number of heavy rainfall events could increase by 36% in the Alpine areas and 70% in the lowlands of the country (between the reference period 1961–1990 and the projection period 2011–2040; Kellermann et al. 2016).

The Austrian Federal Railways (ÖBB Infra AG), along with partners from civil society, the private sector and the government, have the challenging mandate to assess risks, take preventive measures, and ensure the safe and continuous operation of the network. One risk reduction strategy followed is the implementation of structural protection measures, such as avalanche protection galleries or rockfall barriers. In this respect, prioritization of measures and issues of cost-sharing with other governmental stakeholders is a challenge. At the same time, the implementation of structural measures against alpine hazards in Austria – with its approximately 5,000 torrents and 3,800 avalanche paths across the whole territory of Austria – is often not feasible for both economic reasons and aspects of nature and landscape protection. Since technical measures are thus limited in ensuring a commensurate level of safety for railway operations in the alpine topography, there is a strong need for additional (non-structural) risk reduction measures, such as weather monitoring and early warning.

To ensure that rail infrastructure is maintained and resilient against extreme weather events, both the European Union and Austria have established a hierarchy of legal, strategic, and financial frameworks. Due to its Alpine topography,  Austria has some of the most stringent national requirements.

• Federal Railways Act (EisbG - Eisenbahngesetz): Section 42: Provides the legal basis for the ÖBB Framework Plan, a six-year rolling investment program. It mandates that the infrastructure manager must maintain the network in a "safe and operational condition". This provision includes a legal obligation to perform preventative maintenance against natural hazards.
• ÖBB Framework Plan (2024–2029): This is the primary means of execution . It allocates 'EUR 21.1 billion for expansion and 'EUR 4.7 billion specifically for maintenance and fault clearance. The plan explicitly focuses on making the "existing network fit for the climate crisis" by investing in digital monitoring and structural protection measures against alpine hazards.
• Austrian Strategy for Adaptation to Climate Change: This policy framework identifies the "Transport Infrastructure" sector as highly vulnerable. It sets guidelines for:
• Developing early warning systems (like infra:wetter).
• Adjusting technical standards for bridge clearances and drainage systems to handle higher precipitation volumes (the 1-in-100-year flood protection).
• Hydraulic Engineering Assistance Act (WBFG): This act allows for cost-sharing between the railway and the government for protection measures that benefit the broader public, ensuring that expensive Alpine barriers are financially viable.

This national framework supports the implementation of EU transport policies. Those policies  aim for a “sustainable and resilient mobility”, as outlined in the EU sustainable and smart mobility strategy. It also implements the objective of  coherent, efficient, multimodal, and high-quality transport, as pursued by the Trans-European Transport Network (TEN-T) regulation. The latter mandates that projects of "common interest" must demonstrate climate resilience. It specifically requires infrastructure managers to assess vulnerability to climate change (floods, heatwaves) and implement adaptation measures to protect public investments.

Meteorological extreme events pose a great risk for railway infrastructure and the safety of passengers. In the future, climate change will presumably have implications on meteorological hazards in the Alpine region. The objectives of the structural and operational measures, implemented by the ÖBB Infra AG along with its partners, are to minimize direct damage to railway infrastructure where this is economically, technically and environmentally feasible. However, especially in the Alpine mountain environment full protection is not possible and the risk profile due to climate change continuously changes. The objective of the weather monitoring and early warning systems is therefore to ensure safe and continuous operations of the network and the safety of passengers despite the increasing frequency and magnitude of extreme events projected by climate change.

The ÖBB Infra AG follows mainly two complementary risk management strategies. On one hand, risk from Alpine hazards is reduced by implementing structural protection measures. ÖBB Infra AG is mainly responsible for constructing and maintaining protective measures, such as avalanche protection galleries or rockfall barriers. In most cases, it also must finance these measures. Nevertheless, if the planned measures protect also settlements or other infrastructure elements such as roads or energy supply, ÖBB Infra AG cooperates with other state and regional authorities or communities and the protection system can be subsidized within the Hydraulic Engineering Assistance Act (WBFG [1985] 2014).

On the other hand, risk from Alpine mountain hazards is reduced by improving preparedness for response and emergency management. A key element of ÖBB’s risk reduction strategy is the weather monitoring and early warning system called infra:wetter, which is jointly operated by ÖBB and the private weather service UBIMET GmbH. This interactive web-portal, available to the ÖBB staff. It  combines data from own and external weather stations of the ZAMG (Zentralanstalt für Meteorologie und Geodynamik - Central Institute of Meteorology and Geodynamics), radars, satellites as well as local and global weather forecasts with detailed information on the complete railway network in Austria. It provides a calculation of important meteorological parameters like temperature, wind speed, precipitation, snowfall, and the snow line at a local level.

Besides providing individualized and route-specific warnings to approximately 1,800 users, infra:wetter is also used to identify so-called critical meteorological conditions (CMCs) in advance: weather conditions that potentially lead to larger disruptions of train traffic. Those conditions require coordinated action by the Geotechnics and Natural Hazards Management Department of the ÖBB Infra AG. In case a critical meteorological condition is detected with sufficient pre-warning time, a weather warning is issued and a plan of procedures is implemented. This can include the installation of an incidence command that decides about operational safety precautions, such as speed limits, track closures or other temporary mitigation measures. For instance, in the case that heavy snowfall is predicted, measures such as a revised planning of human resources and provision of winter services, or preheating of switch points can be undertaken to ensure the operability of the network. The existence of a functioning weather monitoring and early warning system is also an effective and flexible risk management solution to address the projected changes in the frequency and intensity of climatic hazards due to climate change.

Currently, the system is being further developed to better cope with thunderstorms and heavy rains. The aim is to increase predictability in terms of when and where the routes could be affected.

To address the risk posed by natural hazards, ÖBB Infra AG employs relevant resources and is responsible for major decisions. However, due to the complex situation of alpine hazards, their management within the railway transportation in Austria cannot be handled by ÖBB Infra AG alone, and structural risk mitigation measures in the transport sector have to be aligned with public risk management strategies in many places. Thus, partnerships and vital cooperation between various stakeholders at different administrative levels, i.e. from the local level to the national level, are needed.

At a superordinate level, ÖBB Infra AG cooperates with federal ministries on strategic issues such as decisions in legislation and technical standards. At the level of structural risk reduction measures, ÖBB Infra AG cooperates with regional authorities, communities and the Federal Ministry of Agriculture and Forestry, Climate and Environmental Protection, Regions and Water Management (BMLUK). Regarding non-structural measures, ÖBB Infra AG cooperates with the private sector, academic institutions and regional authorities for operating the weather monitoring and early warning system and to improve risk assessments, e.g. with the avalanche warning services of the Austrian provinces.

The success of the ÖBB’s risk management strategy, particularly of the infra:wetter system and of the structural protection measures against alpine hazards, is rooted in a pragmatic balance between high-tech innovation and traditional engineering.

Success factors

Limiting Factors and Challenges

• Physical and biological Factors: Space is the primary constraint. In narrow Alpine valleys, there is often literally no room to build a new rockfall gallery without infringing on protected habitats or existing settlements. Austria’s strict Nature Protection Laws can delay structural measures for years.
• Social Factors: There is a specific "perception of risk" challenge. While experts see the need for a track closure based on infra:wetter data, the public often views these "preventative" delays as a sign of inefficiency rather than safety, leading to social pressure and resistance to service interruptions. This points out the need for better awareness raising and risk communication.
• Technical Knowledge Gaps: While the system handles snow and wind excellently, flash floods and localized thunderstorms remain a "blind spot." These events happen within minutes and are not to model at the meter-scale needed for rail safety.
• Economic Limits: Total protection is mathematically and financially impossible. With several hundred avalanche paths, the ÖBB must prioritize interventions. This "triage" approach that prioritizes tasks requiring most urgent actions can be politically sensitive if a specific region feels its rail connection is less protected than others.

The harsh mountainous nature of the Eastern Alps, covering 65% of Austria, presents a profound challenge for railway management, as steep slopes and narrow floodplains force infrastructure into high-risk zones for debris flows, rockfalls, and avalanches. This vulnerability was starkly illustrated by the September 2024 floods. Those  caused approximately EUR 100 million in direct financial damage to tracks and tunnels in Lower Austria, while indirect losses from service disruptions were even more severe. Indirect costs often eclipse direct infrastructure damage. They ripple through the entire national economy, affecting both the daily lives of citizens and the reliability of international supply chains. Industries relying on "just-in-time" delivery—such as automotive or chemical clusters—face production halts when raw materials are stranded. The reduction of daily trains forces thousands of commuters into slower rail replacement busses or private vehicles, leading to massive  time wasting.

In 2012, the replacement bus service alone costed around EUR 15,000 per day. Recovering the derailed passenger train costed more than EUR 100,000. Costs of damages to avalanche barriers, track bed, and other infrastructure must be added to that. The Austrian Federal Railways (ÖBB) estimates renewal costs of around EUR 5 million for Tyrol and Vorarlberg.

Unfavourable weather conditions can lead to closures of entire rail networks and traffic routes, mainly due to events such as snowfall, storms and floods. Weather-related delays or failures on transport routes and railway lines generate additional costs for the railway company. From 60 minutes delay, there is a 25% fare refund, even in the case of weather-related delays, as required by the  Regulation (EU) 2021/782 on rail passengers’ rights and obligations. In no other industry is the adherence to schedules and the timely transport of people and goods so important.

Reducing these climate change related fallouts and delays brings several benefits, mainly in terms of avoided cost, ensuring economic activities, reduced payments to passengers and stranded operation staff.

The construction of structural protection measures (e.g. galleries and flood protection systems) can take up to several years for implementation. The implementation of other structural measures such as protective nets against landslides and debris flows is a continuous task run by ÖBB Infra AG. The protective measures focus also on rockfall protection by installation of protective nets which also require continuous maintenance. Currently,  ÖBB Infra AG and UBIMET GmbH systematically analyse weather conditions with regard to anomalies caused by climate change. This allows a better preventive planning of measures.

ÖBB Infra AG and UBIMET GmbH implemented the weather monitoring and early warning system infra:wetter    in 2005 and it is still operational (2026 update).

Structural protection measures such as avalanche protection galleries or rockfall barriers usually have a lifetime of several decades. The weather monitoring and early warning system infra:wetter is a permanent task.

ÖBB-Infrastruktur AG
Line Management and Asset Development
Department for Geotechnics and Natural Hazard Management
1020 Vienna

E-mail: meteo@oebb.at

FP7-funded ENHANCE “Enhancing risk management partnerships for catastrophic natural hazards in Europe” project

INFRA.wetter – Weather Warning and Information System for Railway Infrastructure, The Lakeside Conference. Safety in mobility 2008, https://uic.org/IMG/pdf/weather_information_warning_systems__christian_rachoy.pdf

ÖBB INFRA – For a stable tomorrow. Annual Report 2024 ÖBB-Infrastruktur AG

RISKCAST - Flexible, modular detection and information transmission system for recording and forecasting of natural hazard processes. A project funded under the Pilot Initiative for Transport Infrastructure Research - 2011 (only in German)

Clim_ect. - Climate impact analyses along the ÖBB railway lines. A project funded under the Transport Infrastructure Research 2018 program (VIF2018). Executive Summary  - 2021 (only in German)