Purpose The study establishes complex terrain as a critical dimension in large-scale railway projects. It aims to identify and prioritize risks associated with railway construction under complex terrain. Design/methodology/approach Through literature review of the project under complex terrain, risks were identified and then assessed using integrated method combining Failure Mode and Effects Analysis (FMEA), Fuzzy Stepwise Weight Assessment Ratio Analysis (FSWARA) and Fuzzy Weighted Aggregated Sum Product Assessment (FWASPAS). FSWARA was applied to derive relative importance weights of evaluation criteria, and FWASPAS was used to rank the risks. Risk ranking was tested for robustness through sensitivity and comparative analysis with traditional FMEA. Findings Thirty-three risks were identified, constituting six categories. The risk assessment analysis confirms criticality of the complex terrain challenges with complex geological condition of terrain, geotechnical instability, fault zones/seismic activity, ecological disruption and extreme weather, ranked most critical, all fundamentally linked to terrain complexity. Sensitivity analysis confirmed the stability of rankings under varying weights, while comparative analysis showed improved consistency and discrimination over traditional FMEA methods. Practical implications The findings underscore the need of heightened attention to geological, geotechnical, ecological and natural disaster-related risks in railway construction under complex terrain. The utilized model enhances decision-making accuracy and offers a more robust alternative to traditional FMEA approaches. Originality/value The study presents understudied context of complex terrain railway project risks and utilizes an integrated model combining FMEA, FSWARA and FWASPAS to assessing risk factors.
Ma et al. (2026) studied this question.