Integrated Optimization Of Container Ship-Block Train Transfer Operations In Rail-sea Intermodal Terminals

With the improvement of the comprehensive transport system and the proposal of the Belt and Road Initiative,multimodal transport has become an inevitable trend of China's cargo transport.Besides,rail-sea intermodal transport has become an important component of the multimodal transport system due to its advantages of low cost,large loading capacity,convenient to connect,safety and reliability.Meanwhile,under the New Normal of China's Economy,new requirements have been put forward for the overall energy consumption of transportation.The operational efficiency,effective connection,high energy efficiency and low energy consumption are key targets for the optimization and upgrading of transport structure in China in the future.Rail-sea intermodal terminals are crucial nodes in the entire multimodal transport system,in which the organization and scheduling scheme of the intermodal transshipment can affect the efficiency and turnover of the entire multimodal system,as well as the energy consumption generated.Thus,effectively organizing loading and unloading operations and the turnover of intermodal containers,as well as performing the integrated optimization of containers handling scheduling,are of great significant,which can enhance the intermodal transport service capacity in container terminals and improve the efficiency of handling operations and energy utilization.This paper focuses on the handling scheduling operation and trains transport organization in rail-sea intermodal container terminals.Based on analysis of the integrated scheduling mechanism of intermodal containers flow between ships and trains,handling schedule of containers and distribution template with container trains are studied,while considering actual operational demands in different scenarios in ports.The main research contents are as follows:(1)The framework of integrated optimization theory for container ship-block train transfer operations in rail-sea intermodal ports.To prompt the rail-sea intermodal transport development in container terminals in China ports,some related development foundation,key elements,core conditions and technical difficulties are systematically analyzed.To tackle the tough issue of integrated loading and unloading of ships and trains and to bridge the last kilometer in intermodal terminals,some appropriate operation scenario,handling schedules and operational objectives are defined,three core optimization problems are determined.Then,the overall framework of operation scheduling and organization optimization under the ship-train connection in rail-sea intermodal ports is constructed from the perspective of coordination of transport capacity.(2)Integrated scheduling optimization of multiple handling equipment for ship to train transshipping after ships' arrival in port.Within the overall framework,this section analyzes loading,unloading processes of containers transferred from ships to trains,and studies the integrated scheduling problem of multi-equipment under the intensive handling operations with Quay Cranes-Internal Trucks-Reach Stackers as the main handling equipment.Given that actual operational demands in ports,the coupling mechanism of equipment's operational efficiency and energy efficiency is analyzed,to minimize the Makespan of overall handling process and to minimize the total energy consumption.A mixed integer programming model for integrating equipment scheduling for high energy-efficient operations is established,a hybrid optimization algorithm based on genetic algorithm is designed to solve the model,and some numerical experiments are designed to verify the proposed model and algorithm.(3)Integrated optimization of equipment scheduling and yard space allocation after trains' arrival in port.Within the overall framework,this section analyzes containers transshipping processes between the railway operation area and the container yard area.Then,the integrated scheduling of multi-equipment and yard space allocation are studied,with Rail Mounted Gantry Cranes-Automated Lifting Vehicles-Yard Cranes as the main handling equipment,while considering the bi-directional handling operations of both imported and exported intermodal containers.A mixed integer programming model is established to integrate the equipment scheduling problem and the yard space allocation problem,aiming at minimizing the completion time of all handing tasks,minimizing the total energy consumption of equipment,and allocating the storage locations of export containers.An improved genetic algorithm is designed to solve the model,then the proposed model and algorithm are verified by numerical experiments.(4)Optimization of departure block trains' transport organization with the Ship-Train transfer connection.Within the overall framework,this section analyzes the total processes of containers transshipment between ships and trains at rail-sea intermodal terminals and proposes a method of distribution template with railway trains from the perspective of time and space resource allocation.Based on dynamic changes of container flow's throughput arrived at port and different departure directions transported by block trains,this section analyzes key factors for organizing block trains' distribution template,including trains' departure time,running direction,train frequency and loading scheme.Given that related constraints for model formulation,including railway organization constraints,handling capacity constraints,container flow balance constraints,the distribution template of trains' departure organization optimization model is designed to minimize total containers' storage number in yard from a dynamic perspective.A heuristic algorithm is designed to solve the problem,an evaluation index system is proposed to evaluate the cohesion effect on the rail-sea intermodal transshipment in ports.