Purpose: This purpose of this paper is to evaluate the experiences of public-private partnerships (PPPs) in China's urban rail development, investigates the critical factors impacting on the project viability and derives lessons for future urban rail PPP projects in China and elsewhere. Design/methodology/approach: A case study of the Beijing Metro Line 4 project was adopted as the main research method with semi-structured interviews with senior practitioners and experienced academics as the primary data collection instrument. Qualitative data were collected and subjected to content analysis. Findings: The case study provides six critical factors which are required to facilitate PPP urban rail development: streamlined approval process; robust tendering; strong leadership within the public procuring authority; effective organisational structure and the private sector innovation; commensurate charging approach and government subsidising scheme; and appropriate risk allocation. The research shows that the potential to directly re-apply the Beijing Metro Line 4 model to future urban rail development is limited, but lessons for future urban rail PPPs can still be drawn from the study. Practical implications: The paper serves as an illustration to public procuring authorities and potential private investors on how to structure and manage urban rail PPPs. Originality/value: The research presents an original investigation of China's first urban rail PPP, the Beijing Metro Line 4 project and assesses the applicability of the Beijing model to future PPP projects in urban rail development. © Emerald Group Publishing Limited.