Life Cycle Information Models of Embodied Carbon and Emissions of Railway Track Maintenance

Abstract: The Federal Railroad Administration (FRA) currently provides railroad project sponsors with guidelines for a consistent approach to benefit-cost analysis (BCA) for passenger and freight rail track constriction, capacity expansion and mainline corridor upgrade project proposals. The systematic process of identifying, quantifying, and comparing expected benefits and costs helps decision-makers evaluate trade-offs among alternative transportation investments. The current BCA guidance recognizes that both passenger and freight rail projects may reduce transportation impacts on the environment by lowering emissions of greenhouse gases and other air pollutants, but its focus is on mobile-source emissions of transportation operations. One limitation of the current guidance is that it lacks consideration of emissions due to construction and maintenance of the proposed transportation infrastructure, including the manufacture, transportation, installation, modification, refurbishment and disposal of various track infrastructure materials. This FRA-funded project, being conducted by Michigan Technological University in collaboration with the University of Texas at Austin, will address emissions due to a wide range of track maintenance, rail corridor upgrade, capacity expansion and new track construction projects by integrating the proposed life cycle assessment (LCA) framework into the FRA BCA guidance.
LCA is a method used to assess potential cradle-to-grave environmental impacts of products or processes. For a rail corridor, life cycle emissions of track construction and maintenance include impacts incurred during the mining, extraction, production, transportation and installation phases of all the raw materials and manufactured track infrastructure components associated with construction and maintenance activities; and the impacts due to their eventual end-of-life reuse/disposal. The overall goal of this project is to develop a comprehensive framework for conducting LCA on emissions from various types of track maintenance activities and processes in different track use categories (operational and infrastructure settings), an organized database with a first generation of emissions inventory data, and preliminary rail track maintenance LCA tools.
The project team has proposed a systematic methodology to develop process charts that document the activities, processes, equipment and materials associated with a given maintenance activity. Parameterized Life-Cycle Information Models (LCIMs) derived from these process diagrams have been developed using openLCA, leveraging background data (embodied carbon and emissions of producing various track materials) from the "Federal LCA Commons" and foreground data (equipment fuel consumption and production rates) sourced from industry partners. This presentation will elaborate on our strategy for addressing data gaps and engaging with industry stakeholders possessing deeper insights into maintenance activities which can ensure the reliability of parameters employed in LCIMs.
Additionally, we will present a sensitivity analysis of emissions from track maintenance activities conducted across different life cycle categories (equipment use vs. material use) and the impacts of specific parameters within these categories (e.g., production rate, material transportation). This analysis sheds light on maintenance emissions hotspots, and can help guide industry efforts to efficiently mitigate the carbon footprint associated with track maintenance activities.
Presenting these results and an update on our project will provide a platform to gather practitioner feedback on development of the parameterized LCIMs in collaboration with industry partners.