Research On Distribution Center Selection And Service Network Design Optimization For China Railway Express

With the increasing demand of international logistics,China Railway Express(Hereinafter referred to as: CR express)is also developing rapidly.However,a lot of problems still need to be faced in its organization and operation mode.Based on the background of the transportation organization optimization of CR express,this paper analyses the optimization of the transportation organization of the domestic segment of the outbound freight train.Furthermore,this paper studies the two main factors that restrict the efficiency of CR express outbound freight train transportation organization,including the selection of the freight distribution center and the optimization of the service network design.The main research contents include:1.Domestic Distribution Center Selection.First of all,considering the division of logistics nodes by the government and the experience of CR express operation,27 cities in China are selected as the candidate centers of freight distribution.Then based on the theory of complex network,five evaluation indexes are designed from three aspects: local characteristics,global characteristics and potential attributes of network nodes.These 27 candidate cities are evaluated by the five evaluation indexes in three transportation networks of China Railway,expressway and national highway.Finally,TOPSIS model is used to evaluate the significance of the three network nodes,and combined with the different freight rates and speeds to evaluate the capacity of the nodes.2.Design and Optimization of CR express Service Network in Domestic.On the basis of the network selected by freight distribution center,the frequency service network model is constructed by using the hub-and-spoke transportation mode,and the objective function of the model is to minimize the cost and distribution time.The main constraints are flow balance constraint,capacity constraint,distribution mode constraint and decision variable rounding constraint.At last,an example is designed and Lingo solution is used to get the optimization scheme,which verifies the validity of the model.3.Design the case and verify the validity and rationality of the method.Through the method of selecting the distribution center,8 cities nodes are determined as the freight distribution center,which are Chengdu,Xi'an,Taiyuan,Zhengzhou,Suzhou,Urumqi,Hohhot and Harbin.Then,the OD data between nodes is obtained through investigation,and the optimization scheme is obtained based on lingo solution.Finally,the optimization results are analyzed and compared with the current actual operation plan from the perspective of timeliness and economy.The results indicated that the operation cost of each container is 1078.243 yuan higher than that of the current operation plan,however the whole transportation time of each container is shortened by 0.36 d on average,and the benefit of shortening time is greater than its increased economic cost.At the same time,the enhancement of timeliness can bring continuous benefits to CR express in various aspects,thus the rationality of the optimization scheme can be verified.The conclusion of this paper can effectively solve the problem of disordered competition of domestic freight supply,and has certain guiding significance for the sustainable development and operation of CR express.The service network design model is based on the result of the selection of the distribution center,covering most of the domestic train routes,which has a strong representativeness and improves the service level of the domestic train.