Study On Optimization Of Railway Express Freight Trains Operation Plan

With the continuous adjustment of China's social economy and industrial structure,the demand for social products continues to increase rapidly,the market for express freight products is constantly expanding,and the higher quality of services is placed on the transportation process.How to organize safe,reliable,convenient,rapid transportation is an important issue that our country faces after it put forward the '"cargo registration system".The operation plan is the key document guiding the railway transportation work.Whether it is reasonable or not has a direct impact on the efficiency and level of service in the process of transportation and production,and has a theoretical guiding significance for the actual transportation organization.This paper focuses on the optimization of the express train operation plan:(1)Through the classification of the railway goods,it summarizes the features and transportation requirements of the express goods,and briefly describes the process of the express freight organization.Express train combines train formation plan and passenger trains operating plan characteristics and the service level is higher than that of rail freight transport organization,which is mainly reflected in the train formation,routine,speed,full shaft conditions and operating time etc.(2)Compared with the developed countries in the world,the express freight transportation in our country started relatively late.According to the characteristics of the express freight transportation,some problems still exist in the transport organization.Express freight directs the design of operation plan,at the same time,reasonable and effective operation plan will attract more freight source.Also,the capacity of the rail network,train formation,the traffic flow route and the transportation time all have an impact on the optimization process of the design of operation plan.(3)The optimization model is designed based on the express train service network in which the node is divided into arrival node and departure node.According to whether the arriving node and the departure node are belonged to the same station node,the service arc between the two is set as distribution arc and transit delay arc to represent block swap process.Under the condition of the boundary conditions,aiming at minimizing the cost of all the trains on the rail network and the time cost of freight transportation,the model must satisfy the maximum delivery time constraint of each stock flow,the restriction of service arc capacity and the uniqueness of traffic flow(4)Design an example to solve the model.According to the demand of OD flow demand,the candidate set of service is calculated using K short-circuit algorithm,and solve the model by using a mathematical optimization software,Gurobi,calculated by Python.The final optimization result verifies the validity of the model and the algorithm.