Foreign experience in implementing transport infrastructure megaprojects: limitations of agile Methodologies and adaptation of the Waterfall approach

This study examines foreign experience in implementing transport infrastructure megaprojects, particularly high-speed railways. The research focuses on methodologies for managing and planning large-scale infrastructure projects, as well as institutional and technological factors determining project success. The author analyzes the characteristics of megaprojects, limitations of applying Agile methodologies, and possibilities for adapting the Waterfall approach with elements of flexibility. Particular attention is paid to comparative analysis of high-speed railway development programs in China, France, and the USA (California), including technology transfer strategies, technology localization, institutional architecture, and financing models. The study covers gradual assimilation of imported technologies by Chinese companies, development of proprietary technological platforms (Fuxing series, CRTS III), French experience in creating high-speed transport technologies from scratch, and systemic causes of the California High-Speed Rail project failure. The research employs comparative analysis using qualitative and quantitative parameters for project efficiency assessment. The novelty lies in identifying criteria for successful and unsuccessful transport infrastructure megaprojects from the perspectives of innovation economics, Waterfall planning methodology, and technological learning strategy. The author's particular contribution is substantiating the thesis of general incompatibility of pure Agile methodologies with the physical and institutional nature of infrastructure megaprojects. The main conclusions are: 1) methodology type itself does not determine project outcome; decisive factors are feasibility study quality, completeness of preparatory stages, funding stability, and presence of a strong centralized project owner with internal competencies; 2) Agile methodologies are effective between projects rather than within them: learning and adaptation occur at program and portfolio levels, but not through arbitrary changes during construction of a specific line. The author formulated recommendations for Russian megaprojects, including realistic feasibility study assessment, strict adherence to completing key Waterfall stages, development of standardization and digital platforms, and establishment of centralized management structures.