Railway infrastructure development increasingly makes use of public–private partnerships (PPPs) as a way to help overcome both financing and capacity constraints. The success of public–private partnerships ultimately depends on how well critical success factors (CSFs) are identified and integrated into the projects. Therefore, this study is intended to identify the most important CSFs that contribute to the successful delivery of PPP projects undertaken by Indian Railways and to create a framework to assist policymakers with developing sustainable PPP models. The empirical results were derived through a combination of an extensive academic and policy literature review, as well as through primary data collection using semi-structured interviews and a questionnaire-based survey of senior officials, managers, and executives affiliated with Indian Railways, railway special purpose vehicles (SPVs), public sector undertakings (PSUs), financial institutions, and academia. The exploratory factor analysis (EFA) of the 177 valid responses received established that three main factors or dimensions contribute to the success of public-private partnerships (PPPs). These factors/dimensions are operational efficiency (project governance, stakeholder alignment, and contract enforcement), financial viability and risk management (sources of finance, risk-sharing mechanisms, and crisis resilience), and regulatory/legal framework (the need for policy certainty, independent regulation, and dispute resolution). This study also aims to develop comprehensive frameworks and PPP models that incorporate established best practices to meet the requirements of Indian Railways as well as other railways in terms of developing sustainable and effective models. This study represents an important academic contribution by developing an original and contextualised critical success factor (CSF) framework relevant to India's railway PPP projects and provides actionable policy recommendations that can enhance private sector involvement, promote financial sustainability and improve the long-term performance of railway infrastructure in India.