Life Cycle Assessment of a heavy metro train

The railway system represents one of the most resource-efficient answer to the ever-growing demand for transport service. Development trends for the following years project substantial increase in this sector. To date, environmental effects caused by railway transport services have been rarely inspected systematically and existing studies focus on single typologies of environmental aspects, like energy consumption and air emissions. The article presents a predictive Life Cycle Assessment (LCA) of a heavy metro train that will operate in the urban area of Rome. A predictive analysis on recyclability/recoverability at the end of life has also been performed according to the ISO 22628. The LCA inventory captures the whole vehicle Life-Cycle (LC) subdivided in four stages: Material acquisition, Manufacturing, Use and End of life. In comparison with existing studies, this work examines a broader range of impacts to human and ecosystems health using primary data supplied by vehicle manufacturers whenever possible to reduce the uncertainty of results. Results show that Use is largely the most influential stage for the majority of the considered impact categories. This fact is due to the energy intensity of Use stage since it accounts for almost the entire amount (98.3%) of electricity consumed during vehicle LC. Material acquisition is the second most influential stage based on resource consumption and emissions during extraction of Iron and Bauxite: vehicle parts that mainly contribute to impacts of Material acquisition are body structure and bogies. The impacts associated with Manufacturing and End of life are low compared to the other stages. The projected recyclability and recoverability rates at the end of life stage are respectively 87.4% and 92.1%. A sensitivity analysis of the LCA results stresses the influence of vehicle occupancy on the electricity consumption during operation and the overall LCIA results. In light of LCA results, major improvement potential is identified in the reduction of electricity consumption during use stage, primarily due to Traction and Heating systems. The key recommendations for future design strategies are the decrease of vehicle mass by the application of lightweight materials for metro construction and the improvement of efficiency of the Heating system.