Abstract: Conventional metro-based urban underground logistics systems (M-ULSs) face challenges such as line detours, low network coverage, and insufficient operational performance. To address these challenges, an M-ULS network expansion scheme is proposed, focusing on improvement at the front, trunk, and end levels. In addition, a freight performance evaluation model is established that considers the transportation capacity, time, and cost. Finally, the effectiveness of the proposed design is validated through simulation using the Nanjing metro. The results demonstrate the following: (1) The M-ULS network exhibits superior operational performance compared to combined multiline passenger and freight transport networks. Specifically, the network capacity increases by 103.1%, while the channel load rate, transportation time per unit, and transportation cost decrease by 41.7%, 29.21%, and 51.3%, respectively. (2) The high M-ULS freight performance is primarily attributed to enhanced capacity, expanded coverage, and optimized freight flow path achieved through hybrid marshaling. (3) Prioritizing the construction of front and trunk freight networks is crucial. Further improving the M-ULS transportation efficiency depends on the scientific network expansion layout and the reasonable allocation of transit node capacity redundancy.

Key words: underground logistics system, metro, network design, freight operating performance