Research On Transportation Organization Of Railway Container Passengerized Transport System

The existing railway freight transport system in China adopts the "organizational" mode,and the organization of train operation aims at "utilizing the capacity of railway transportation equipment and improving the utilization efficiency of locomotives and rolling stocks".This mode can solve the problem of long-distance transportation of freight with large traffic volume(e.g.energy,raw materials and small quantities of high-valued commodities),but the remaining large amount of scattered high-valued commodities need to be transported with several times of transfers at the technical stations,resulting in low time efficiency.However,in recent years,with the adjustment of economic structure,the freight demand in China has undergone significant changes.The demand for high-valued commodities has increased rapidly.The high-valued commodities are usually light in weight,small in volume and large in batches.Most of them are suitably containerized cargo,which require high safety and rapidity in transportation and are suitable for container transportation.In this context,railway container transportation will play a more important role in China's freight transportation,but at present,the market competitiveness of railway container transportation in China is poor,and its market share is far lower than that of road transportation.Therefore,it is of great practical significance to optimize the railway container transportation organization and improve its the competitiveness.Based on the analysis of the problems of existing organization mode of railway container transportation in China,this paper proposes to establish a new railway container transport system,which is the railway container passengerized transport system(hereinafter referred to as the new container transport system).The key technologies,the theory of transportation organization and the line plan of the new container transport system are deeply studied in order to provide an effective solution to the railway container transportation problems in China.The research contents of this paper are as follows:(1)In terms of theoretical research,this paper seizes the characteristics of single organization object and convenient organization of container transportation,and puts forward the railway container passengerized transport system according to the scale of railway network,technical level and the characteristics of freight transportation demand in China.At the same time,the four key technologies of the new container transport system are studied in detail,which are the technologies of passengerized operation of container trains,network transportation,station layout design and transformation and equipment resource allocation,respectively.On this basis,in order to ensure the operational effect of the new container transport system,this paper studies the collection and distribution mode,the transportation organization plan,the station operation organization,the management information system,the transportation product design and the tickects selling,trying to build a relatively complete transportation organization theoretical framework for the new system.(2)In terms of optimization modeling,this paper studies the line planning problem for the new container transport system.Firstly,the framework of phased optimization approach is proposed,which decomposes the line planning problem into the subproblem of line optimization and frequency setting and the subproblem of train stop planning.Then,for the subproblem of line optimization and frequency setting,the mathematical optimization models under the pre-and post-operational scenarios of the new container transportation system are proposed.The former mixed integer linear programming model takes the minimum cost of the enterprise(including the fixed cost for constructing lines,the variable cost for operating trains and the container transfer cost)as the objective function,and considers the constraints of container flow conservation,container transfer and transit period.The latter multi-objective integer programming model considers the capacity constraints.Based on the determining of the physical path of containers,the minimum transportation cost and total number of transfer times are used as the objective functions.Both models adopt the modeling idea of “line pool”,and specify the uniqueness of the physical path and transportation plan when modeling the container distribution.Finally,for the subproblem of train stop planning,a mixed-integer linear programming model is proposed,in which the objective is to minimize the total number of stops.In addition,the specific container-to-train distribution and the utilization rate of each individual train are considered.(3)In terms of algorithm design and case analysis,this paper both considers the efficiency and quality of model solving.For the optimization model under the pre-operational scenario,this paper designs an adaptive large neighborhood search heuristic algorithm.A 17-node transportation network case is used to verify the feasibility of the model and algorithm.The sensitivity analysis of the train speed and train length parameter are carried out.Furthermore,six evaluation indexes,which are the container transportation volume,the average train frequency,the train utilization rates,the direct container rate,the delivery speed and the transit period,respectively,are selected to evaluate and analyze the obtained results.And a comparative analysis with the existing freight system was carried out.The consequences prove that the new container transport system performs better in terms of the container transportation volume,the average train frequency,the delivery speed and the transit period,while it also sacrifices part of the resource utilization efficiency.For the optimization model in the post-operational scenarios,this paper firstly uses the linear weighted sum method to transform the model into a single-objective model,and then solves the new model by the Cplex solver.Finally,a transportation network with 51 nodes is taken as an example to obtain the Pareto boundary for the problem.For the train stop planning optimization model,it is solved by the Cplex solver in this paper and two numerical experiments are provided to demonstrate the practicability of the model.An illustrative example is performed primarily,where the relationship between stop plans,distribution plans and train utilization rates are analyzed.A large-scale example using the Lianyungang-Alataw pass railway corridor is also designed to conduct sensitivity analysis.There are 56 figures,24 tables and 155 references in this paper.