LCA of Different Construction Choices for a Double-Track Railway Line for Sustainability Evaluations

The international commitment to achieve carbon neutrality in the next few decades has oriented human activities towards the preservation of natural and non-renewable resources. In this context, a great research effort has been devoted to the search for sustainable solutions for the infrastructure construction sector, based on a thorough assessment of the environmental impact (EI). In this regards, Life Cycle Assessment (LCA) is considered one of the main components of Environmental Impact Assessment (EIA) and, for a comprehensive analysis, all the costs incurred by stakeholders during the useful life of the infrastructure should also be taken into account, applying the Life Cycle Cost (LCC) methodology. So far, there is a lack of combined LCA and LCC analyses of railway projects to support a proper sustainable decision-making process at a project level. Therefore, this study aimed to contributed to this topic by determining the environmental effect and related costs of different planning and construction choices in terms of material and maintenance strategies. For this purpose, first, an LCA of typical railway infrastructures with a ballasted track was developed. The case study considered two different functional units of a double-track railway line: 1 km of embankment section and 1 km of a cut section, in straight alignment. After defining five alternative railway infrastructure scenarios with different materials (virgin or recycled material) and construction methods (e.g., lime stabilization), two different railway track maintenance approaches were analysed. SimaPro was used to analyse the case study, and the results were compared with those obtained using the PaLATE software, suitably adapted for use in the railway sector. Finally, a cost analysis was carried out using Life Cycle Cost (LCC) methodology for all the scenarios analysed. The results obtained in terms of EI and related costs of each scenario provide useful information, allowing a sustainable planning approach: as a general result, the initial construction phase always involves the larger part of the total environmental impact while the material production is the most polluting phase, reaching percentages always higher than 50% of the total.