A Study on the Dual Allocation Strategy of Fixed and Moving RTGs in Horizontal Container Yards

With the continued growth of global container traffic, the efficient operation of yard resources has become increasingly critical, particularly in transshipment-focused ports. In terminals with horizontal yard layouts, the complexity of resource management is further intensified by imbalances in workload between blocks, temporal fluctuations in demand, and increased reshuffling due to high yard utilization. This study develops a static resource allocation model based on Mixed-Integer Linear Programming (MILP), which categorizes RTG (Rubber-Tyred Gantry Crane) resources into fixed and moving types and quantitatively distinguishes their respective roles and deployment strategies. The proposed model incorporates the characteristics of horizontal yard structures and group-based resource sharing schemes, while also accounting for inter-shift task carryovers and reshuffling behaviors driven by yard utilization. The model's validity is verified through a case study using real operational data, and sensitivity analyses are conducted on key parameters such as RTG productivity, yard utilization rate, and inter-block travel time. The results demonstrate that an integrated deployment strategy for fixed and moving RTGs can enhance operational efficiency by ensuring both temporal coordination and spatial flexibility in resource allocation. This study offers a practical foundation for yard resource planning in container terminals and highlights the need for future expansion toward dynamic allocation models incorporating real-time data.