Efficiency and energy consumption of the automated container yard with twin rail-mounted gantry cranes considering crane scheduling strategies and handshake area designs

This study investigates the effects of twin rail-mounted gantry crane (RMG) scheduling strategies and handshake area designs on container yard efficiency and energy consumption. A handshake area is set for temporary storage of containers within each block, enabling the cooperation and interference avoidance of twin RMGs. Considering the complexity and dynamics, we establish a simulation model for the twin RMG operations with agent-based and discrete event simulation modeling. Container relocation, microscopic movements of RMGs, and stochastic arrivals of automated guided vehicles (AGVs) and external trucks (ETs) are simulated, and the corresponding efficiency and energy consumption are quantitatively estimated. By testing the six RMG scheduling strategies and thirteen handshake area designs, the results show that the 2-OPT RMG scheduling strategy (an optimization heuristic that attempts to find the schedule with the minimum makespan) outperforms the other strategies in terms of efficiency. However, the optimal RMG strategy for minimal energy consumption depends on the ratio of landside and seaside requests and handshake area settings. Furthermore, the location of the handshake area significantly affects the efficiency and power consumption of AGVs and RMGs. This study can provide decision support to improve the efficiency and reduce energy consumption of the twin RMGs by selecting a specified combination of the RMG scheduling strategy and the handshake area design.