Addressing the current challenges in urban rail transit line reconstruction, such as insufficient network synergy, path dependency in equipment updates, and the lack of upgradability design, this study explores theoretical innovation directions. It proposes key strategies, including incorporating upgradability into the equipment performance evaluation system, decoupling equipment from lines for networkoriented reconstruction, and improving the overall network functionality through clustered line reconstruction. These theoretical innovations aim to systematically promote the reconstruction of existing lines, reduce the cost of equipment upgrades, improve maintenance efficiency, and drive the sustainable development of the urban rail transit industry. Based on the framework of Guidelines for reconstruction of existing urban rail transit lines in China, this study addresses critical challenges in urban rail transit reconstruction, including insufficient network coordination, path dependency in equipment upgrades, and inadequate upgradability design. It proposes a comprehensive theoretical framework with four key innovations: integrating "upgradability” into equipment performance evaluation systems; implementing networkoriented decoupling of equipment systems from physical infrastructure; enhancing overall network functionality through clustered line reconstruction approaches; and developing derivative, regenerative, and symbiotic systems for rail transit reconstruction based on the "productionlivingecology" theory of urban renewal. These theoretical advances provide systematic solutions to optimize network functionality, reduce equipment replacement costs, enhance maintenance efficiency, and promote sustainable development in the urban rail transit sector. The proposed framework offers valuable guidance for policymaking and implementation strategies in urban rail transit modernization.

urban rail transit  /  existing line reconstruction  /  theoretical innovation  /  equipment upgradability  /  equipment decoupling reconstruction  /  line cluster