Scheduling Optimization Of Loading/Unloading-transfering Operations Considering Rehandling Activities In Railway Container Terminals

Modern rail-road container terminals serve as important consolidation nodes in intermodal transportation networks where containers are transferred between freight trains and trucks.With the support of national initiative “The Belt and Road”,the throughput of the railway container terminal is continuously expanding.Due to the limitation of the stacking space(including container stacking area and auxiliary storage area)and unfixed retrieval time,there should be a corresponding deterioration critical threshold for any movement tasks during the complicated loading/unloading transportation scheduling process.If the task cannot be handled before the time threshold,other containers will stack on the top of it.Rehandling operation must be carried out when handling the task.In addition,the railway container terminal is different from seaport container terminal in various aspects such as layout and operational facilities,and the related rich theories and methods of operations management in seaport container terminals can not be directly applied to the railway container terminal.In that case,the loading/unloading-transfering scheduling strategy is extremely lacked in the railway container terminals.Therefore,this paper starts with container flow,functional zone,and resource allocation for distinguishing the similarities and differences between railway container terminals and seaport container terminals,and integrates the inevitable and worthless rehandling operations to the gantry crane scheduling problems.Apart from these,a layout with handshake area is proposed to apply the main loading/unloading area of railway container terminals.This article considers the following aspects:(1)A review of the development history of domestic and international railway container transportation,the release of relevant strategies,guidelines and the application of rehandling operations and deterioration functions in recent years are carried out.At the same time,the internal processing procedures and functional requirements with seaport container terminals are analyzed.The research directions and aims of resource scheduling problems are summarized in railway container terminals.(2)Single crane scheduling problem is firstly studied in which the step-deterioration function is used to characterize the transferring time for rehandling operation.And an improved genetic algorithm is designed to solve this problem,linear reverse order crossover operator and random recombination mutation operator are proposed to generate new population.Besides,local neighborhood search is combined to refine the chromosome after the genetic operators are manipulated.(3)For the collaborative scheduling of multiple gantry cranes with rehandling operations,precedence relationship,interference constraint,boundary constraint and safety margin have been taken to consider to establish a mixed-integer programming(MIP)model.At the same time,mathematical programming and adaptive large-scale neighborhood are combined to generate a new heuristic method named Adaptive Neighborhood Search Programming(ANSP)with high solution quality to solve this problem.(4)To balance the efficiency of the yard,a layout with handshake area which is used to temporarily storage containers in the loading/unloading operation area is proposed.With consideration of delivery vehicles and task attributes such as container trucks and container trains,several priority heuristic rules are designed based on the operation characteristics of twin container crane scheduling problem.And the impact of the presence or absence of handshake area on the multiple cranes scheduling problem has been compared and analyzed.