Weather phenomena can result in severe impacts on railway infrastructure. In future, projected changes to the frequency and/or intensity of extreme weather events could change weather–infrastructure risk profiles. Infrastructure owners and operators need to manage current weather impacts and put in place adequate plans to anticipate and adapt to changes in future weather risks, or mitigate the impacts arising from those risks. The assessment of the risk posed to railway infrastructure from current and future weather is dependent on a good understanding of the constituent components of risk: hazard, vulnerability, and exposure. A good understanding of the baseline and projected future risk is needed in order to understand the potential benefits of various climate change adaptation actions. Traditional risk assessment methods need some modification in order to be applied to climate change timescales, for which decisions need to be made under deep uncertainty. This review paper highlights some key challenges for assessing the risk, including: managing uncertainties; understanding weather‐impact relationships and how they could change with climate change; assessing the costs of current and future weather impacts and the potential cost versus benefit of adaptation; and understanding practices and tools for adapting railway infrastructure. The literature reveals examples of progress and good practice in all these areas, providing scope for effective knowledge‐sharing—across the railway infrastructure and other sectors—in support of infrastructure resilience and adaptation.This article is categorized under: Assessing Impacts of Climate Change > Evaluating Future Impacts of Climate Change

This paper describes the results of experimental work to determine the structure of the slipstream and wake of a high speed train. The experiments were carried out using a 1/25th scale model of a four-coach train on a moving model rig (MMR). Flow velocities were measured using a rake of single hot films positioned close to the model side or roof. Tests were carried out at different model speeds, with and without the simulation of a crosswind. Velocity time histories for each configuration were obtained from ensemble averages of the results of a number of runs. A small number of particle imaging velocimetry (PIV) experiments were also carried out, and a wavelet analysis revealed details of the unsteady flow structure around the vehicle. It was shown that the flowfield around the vehicle could be divided into a number of different regions of distinct flow characteristics: an upstream region, a nose region, a boundary layer region, a near wake region and a far wake region. If the results were suitably normalized, the effect of model speed was small. The effect of crosswinds was to add an increment to the slipstream and wake velocities, and this resulted in very high slipstream velocities in the nose region.

This paper describes a series of extensive and unique full-scale measurements of the slipstreams of trains of various types that were carried out as part of the EU-sponsored AeroTRAIN project, together with the analysis of the experimental data. These experiments were carried out with the fundamental aim of seeking to reduce the complexity of the current technical specifications for interoperability (TSI) testing methodology. Experimental sites in Spain and Germany were used, for a range of different train types – high-speed single-unit trains, high-speed double-unit trains, conventional passenger units and locomotive/coach combinations. The data that was obtained was supplemented by other data from previous projects. The analysis primarily involved a study of the ensemble averages of the slipstream velocities, measured both at trackside and above platforms. The differences between the flows around different train types were elucidated, and the effect of platforms on slipstream behaviour described. A brief analysis of the effects of crosswinds on slipstream behaviour was also carried out. Through a detailed analysis of slipstream velocity components, the detailed nature of the flow around the nose and in the near wake of the train was investigated, again revealing differences in flow pattern between different trains. Significant similarity in the far wake flows was revealed. These fundamental results form the basis for the detailed discussion of the proposed TSI methodology that will be presented in Part 2 of this paper. Overall the results enable the nature of the flow field around trains to be understood in far greater detail than before, and also allow the developments of a revised TSI methodology which is more efficient than current practice.