Research On Network Nodes Programming Method Of Railway Express Freight Transportion

With rapid development of Chinese economic, the demands for the daily chemicals, precision instruments and other fast goods are growing quickly. Relatively express freight has a great demand for transport requirement, occupation for express freight transport market has become the key to winning transport market. Railway enterprises have a low market share, and there existing insufficiency in Chinese railway freight transportation network node partition, in addition, the current railway express transport network didn’t distinguish with the general freight transport. As the most basic unit of express organization, network nods should be planned scientific and reasonable. This paper selected the appropriate mode of railway express network, and combined with the characteristics of railway express freight transport to give a hierarchical planning of network node.This thesis analyses the existing express network and freight network modes, considering the requirements of timeness and convenience of railway express, and in combination with the requirement of saving transportation cost and achieving the benefit, ultimately ensures a viable hybrid hub-and-spoke network mode. Based on this network mode, this thesis proposes a node planning model based on the pure hub-and-spoke network, to minimize the cost of transportation railway, limit the number of transit hub constraint node connection between the transport path, give full play to the role of hub aggregation node and seek scale effect of transport. This thesis assumes that there is a OD flow of the straight line which is allowed to pass directly, so as to ensure the timeliness of the transportation and reduce the unnecessary transit links. According to complexity of the model and the characteristics of express freight transport, the thesis proposed a two-stage heuristic algorithm to solve the model. The first stage is the use of indicators and the establishment of cluster analysis to detennine the number and location of railway express network hub node, the second stage is the use of improved algorithm to determine the assignment of railway express freight hub nodes. In order to demonstrate the feasibility of the method, this thesis calculates total network cost of railway express transport network, at the same time calculating the cost of the transport network which based on shortest path and the pure hub-and-spoke network that using Tabu Search Algorithm. Further more the thesis compares the volume of transit freight, the calculation indicates that the selected node planning method can give less cost and transit freight of the network than other methods, which corresponds the requirements of the railway express. It can offer a reference for the development of Chinese railway express freight transport.