Climate change risks and vulnerabilities for rail transport assets and operation were identified and consequent adaptation measures proposed as part of the feasibility study of the railway modernization project. Such analysis was elaborated according to the guideline “Methodological Handbook on Assessing Climate Change Impacts on Major Transport Projects” (in Slovakian), which was developed in 2018 by the Transport Research Centre of Slovakia and consultants for the Ministry of Transport and Construction.

Specifically, risk and vulnerability assessment was elaborated for individual sections of the railway under consideration, integrating the aspect of exposition (expected climate change phenomena affecting rail transport) and sensitivity (extent of which the system is susceptible to be influenced by climate change impacts). Risks were attributed to the railway sections and railway components (e.g. bridges, tunnels) according to the following categorization:

• Insignificant (blue); risk can be addressed through standard technical design of railway assets or within normal operation.
• Small (green); risk requires partial change of technical design or operation.
• Medium (yellow); risk requires significant change of technical design or risk operation management.
• Significant (red); risk requires fundamental change of technical design or emergency management;
• Catastrophic (black); risk can lead to long-term closure of operation or damage of railway assets. Alternative routing is highly recommended.

Based on the type and magnitude of risks identified, adaptation responses have been proposed for the relevant sections of the corridor and incorporated in project documentation part of the preparatory and design phase. Proposed adaptation measures can be grouped in three categories:

• Technical options, increasing resilience of essential railway infrastructure to extreme weather events and climate change trends. These measures, which are aimed at preventing disruption of infrastructure availability, include: (i) wind-proofing of the catenary system (e.g. able to withstand the wind speed exceeding 30 m/s); (ii) increased capacity of the drainage system, such as culverts able to cope with higher quantity of water and improved drainage of railway subgrade, tunnels and bridge structures; (iii) increased railway alignment above the limit of potential flood (betweenQ₁₀₀ to Q₁₀₀₀ depending on the on-site situation); reducing slope incline as prevention against landslides; (iv) resistant bridge structures and deep bridge pillars; (v) use of highly water resistant building materials for railway subgrade and other components; (vi) flexible way of mounting rails, which significantly reduces the deformation of rails due to extreme temperatures; (vii) installation of structural protection systems (e.g. windbreaks, retaining walls, embankments).
• Management options, providing solutions when extreme weather events occur and infrastructure disruption takes place. These options help minimize negative impacts of extreme events and include: (i) increased maintenance and control of sections at risks, e.g. equipping switches, rails and catenaries with detectors monitoring temperature (for overheating and freezing), icing, snow precipitation or wind speed; (ii) provision of substitute bus service in the event of temporary interruption of rail transport; (iii) ensuring alternative railway routes and efficient emergency transport management; (iv) measures pertaining to environmental management (e.g. river basin reforestation).
• Early warning system, monitoring and forecasting, aiming to increase preparedness and enable traffic management measures to be taken in advance. This typology of measures relies on the implemented and operative monitoring, forecasting and alerting system of Slovak Hydrometeorological Institute (SHMI); it deals with a “railway tailored” monitoring and forecasting system which focuses on the events particularly harmful for railway, such as strong wind, icing, flooding or heavy snowfall. By means of providing early warning system, the negative impact of extreme weather events on rail transport system and the whole economy will be minimized.

Part of the proposed measures has been implemented in those sections of the railway corridor that have already been modernized. For example, construction works are currently underway in the corridor section between the towns of Puchov and Povazka Tepla (15.9 km long), including two tunnels (respectively 1.1 and 1.8 km long) and three major bridges over the Váh River and the water reservoir Nosice. The whole corridor section Puchov-Zilina (44 km long) is expected to be completed by the end of 2021. This is the remaining corridor section to be modernized between Bratislava and Zilina (approximately 200 km long), part of which has been modernized during the previous programming period (2007–2013). Adaptation measures in these sections include: measures to ensure flood protection up to Q₅₀₀ flood level, drainage of the railway subgrade, and retaining walls reinforcing slopes with high risk of instability. All bridges and tunnels are designed to withstand floods and torrential rainfall (e.g. through isolated bridge decks, resistant bridge pillars) and must be tested for static and dynamic load before they are put in regular operation.