Identifying Early-Stage Risks to High-Speed Rail: A Case Study of the Sydney–Newcastle Corridor, Australia

High-Speed Rail (HSR) has long been proposed as a transformative infrastructure project for Australia; yet, despite multiple feasibility studies and significant government expenditure, it remains unrealized. This study investigates the key barriers preventing HSR implementation. To achieve this, a novel mixed-methods approach that triangulates a comprehensive literature review, in-depth expert interviews, and broad stakeholder survey was employed. The Analytic Hierarchy Process (AHP) was used to quantify the relative importance of the identified barriers. Simultaneously, qualitative insights were gathered through interviews with industry leaders, government officials, and infrastructure experts. This dual approach provided a comprehensive understanding of the challenges. The findings highlight the importance of external factors. These include political uncertainty, financial constraints, and systemic logistical challenges, which go beyond technical feasibility. Based on these insights, this research identifies critical early-stage risks and contributes to a re-evaluation of HSR not solely as a transport solution but also as a vital tool for regional development. Refining cost and time estimation methodologies using reference class forecasting, fostering proactive political engagement to secure bipartisan support, enhancing private sector collaboration through early contractor involvement and risk-sharing mechanisms, and developing a national upskilling framework to address workforce shortages were also key findings. The study has garnered industry recognition and support, with experts acknowledging its contribution to the ongoing discourse on HSR implementation in Australia.