Resilience Assessment and Enhancement for Metro Complex Equipment and Facility Systems: An Integrated Approach Combining Complex Network and FRAM Models

Urban metro systems (UMS) consist of complex equipment and facility systems (CEFS), characterized by interdependencies, cascading failure effects, limited risk tolerance, and significant management challenges. Enhancing their resilience is crucial to improve UMS’s ability to withstand disturbances and ensure safe and efficient operations. Current research on UMS resilience mainly focuses on network structure and service, with limited attention given to the physical infrastructure—specifically the CEFS that support UMS operations—especially regarding system complexity and cascading failure effects. This study presents an innovative hybrid framework for quantitatively assessing and enhancing the resilience of CEFS. By integrating the functional resonance analysis method (FRAM) into complex network (CN) modeling, the proposed CN-FRAM model extends node and edge information to account for system topology, component performance, and functional variability, while also incorporating cascading failure effects. This approach allows for more accurate predictions of failure impacts and a comprehensive assessment of system resilience across various recovery strategies throughout the entire disruption-recovery cycle. Additionally, the study proposes and validates multistage resilience enhancement strategies for pre-, during-, and postdisruption phases, with a particular focus on implementing optimal repair strategies. The results demonstrate the effectiveness of these repair schemes in maximizing system resilience, providing valuable insights for UMS management and enhancing the system’s ability to recover from disturbances.