Research On High-speed Rail Express Transport Plan Considering Freight Time Limit Demand

With the steady growth of our country’s economy,diversified express transportation demands such as rapidity,punctuality,and safety have put forward new requirements for the existing logistics transportation system,and the demand for high-quality express transportation has continued to rise.At the same time,with the gradual improvement of our country’s high-speed railway network,its characteristics of rapidity,punctuality and high safety have laid a good realistic foundation for meeting the demand for high-quality express transportation.In recent years,China State Railway Group Co.,Ltd.has been continuously exploring the high-speed rail express business,but there are still problems such as unclear product positioning,incomplete technical equipment and insufficient utilization of remaining capacity.At the same time,high-speed rail express goods has important attributes such as miscellaneous categories,small OD volume,and high timeliness requirements.How to compile a high-speed rail express train transport plan and match the appropriate transportation strategy for different attributes of the freight flow is an urgent problem that needs to be solved.Therefore,this paper analyzes the market competitiveness and transportation organization mode of high-speed rail express,and discusses the compilation and optimization of the high-speed rail express transport plan based on the forecast results of freight flow and comprehensively considering the demand of freight time limit.Major studies include:(1)In the theoretical basis,the current high-speed rail express business process is firstly summarized,which serves as the theoretical constraint basis for the model construction in the following sections;secondly,the different high-speed rail express transportation organization modes are analyzed,and the technical equipment and other conditions required for high-speed rail express are summarized as model assumptions.Then,quantitatively calculate the upper limit of theoretical carrying capacity under different transportation modes,as the basis for setting relevant parameters in the following paragraphs;finally,analyze the market competitiveness and prospects of highspeed rail express,as the realistic basis for the preparation of transport plans.(2)In the freight flow forecasting process,firstly,a variety of forecasting methods are used to predict and compare the express market demand;secondly,the attraction intensity of urban freight flow is analyzed by combining factor analysis method and trade gravity model,so as to predict the OD freight flow between cities;Finally,the characteristics of transport ways are analyzed,and generalized utility functions of different ways are constructed to calculate the express sharing rate of high-speed rail and the proportion of freight flow of different service products.(3)In the optimization of transport plan,the theory and method of two-stage compilation based on the alternative set of high-speed rail express transport plan are studied.In the alternative set generation stage,according to the particularity of goods transit,a train operation time-space network is constructed,the transport plan alternative set is abstracted into a time-space network path problem,and an improved Yen algorithm is designed to solve it;the second stage takes the transport plan alternative set obtained in the first stage as the basic network,designs a time-space-state network to describe the transportation process of the freight flow,and considers the time-limited demand of the freight flow,thereby transforming the transport plan optimization problem into a network multi-commodity.The flow distribution problem is solved based on an adaptive genetic algorithm.The model comprehensively considers practical constraints such as loading and unloading capacity limitations,operating conditions and organizational conditions,and aims at freight revenue,transportation costs,loading and unloading costs,transit costs and delay penalties,and compiles high-speed rail express transport plans from the perspective of overall planning,so as to maximize the efficiency of transportation.It may meet the demands of high-speed rail express transportation and maximize operating income.(4)This paper designs the high-speed rail express transport plan based on the HarbinDalian high-speed rail.Predict and analyze the express freight flow data in the cities along the high-speed rail line in 2023,and combine the actual train diagram information to organize the transport plan for the next 180 freight flows at 15 OD points.The results of the case solution conform to the principles of model time limit priority,sufficient capacity,and maximization of operational benefits,which proves the effectiveness of the model and algorithm.