The growing interest in the literature on addressing justice and equity in transportation has spurred the need for specific evaluation methodologies. This study proposes a comprehensive methodology for incorporating justice principles in evaluating transportation projects and applies it to a railway case study in Chile. The proposal seeks to measure the impact of implementing specific projects on regional transport justice. This work represents a unique contribution to the literature. To our knowledge, it is the first documented experience attempting to incorporate justice principles developed by Martens (2017) into railway transport projects. It emphasizes standardizing critical processes, such as data acquisition, group and opportunity characterization, and determining appropriate sufficiency thresholds. The proposed methodology advances the theoretical understanding of justice in transportation and provides a practical tool for evaluators and planners. By establishing clear guidelines, this approach can inform critical decisions in the planning and execution of transportation projects, thus promoting a more equitable and just approach to the development of railway infrastructure in Chile.