Research On Freight Rail Network Complexity

Rail network as the lifeline of railway transportation,is the material basis for the transport service. With the increasing of the road network density and the building of the passenger-dedicated line, it achieved a separation of passenger and freight in some areas,and the transport capacity had been greatly improved. Study the reliability of the freight transport network and the train running late event spreading in the network, has great realistic meaning of ensuring the punctuality, high efficiency and safety of freightage. In recent years, boom of study complex networks to the theory more perfect. Complex network theory is applied in various subject areas.The use of complex network theory to study the rail network is a new perspective.This paper, on the basis of primary domestic and foreign research, took the real network as the research object, combining with the characteristics of railway freight transportation technology work and freight reform development direction in China, further study the complexity of railway freight transportation network.Firstly, abstracting the freight rail network from two aspects of geographically facilities and traffic, got the corresponding railway geography network and traffic network.Through analysis the static statistical features of two kinds of network, discovered that its has the shortest distances between the network nodes and node degree distribution follows a power-law distribution, so we determined that the two networks are scale-free networks with small worldwide.Geographical network relative to the traffic network, its clustering coefficient is low, tending to the tree network.However, whether it is a small world and scale-free sex are more obvious in the traffic net. And then, this paper compared the node which betweenness ranks in the top fewplaces in the two networks, analyzed the importance of the larger betweenness node which occupied the position in the network.Secondly, directing against the features of these two networks, this paper build different reliability index, used the C Programming Language to simulation the reliability of network. In the use of web-based geographical network connectivity index in the research, this paper begins from two aspects of the whole network connectivity and single node vulnerability, used the index which mainly took the connected efficiency for reliability analysis. Simulation results show that the reliability of the network in the face of random attack higher than deliberate attack, and faceda deliberate attack on betweenness has lowest reliability. And then, simulation the influence on the reliability of the network based on the network structure entropy index of traffic network of a single node failure, draw some betweenness and degree is not prominent nodes in the network reliability has a greater impact.Lastly, This paper established running late propagation models in the traffic net based on the spreading mechanism of epidemiological in complex networks. This paper study the late event spread of the network by simulation. Simulation shows that, under non-human intervention, the speed of propagation of the train running late depends largely on the node degree of the originator which was late, the key factor which control train delays is how much the connection direction of the originator which was late, the results corresponds to the conclusion that the spreading mechanism of epidemiological in complex networksrely depend on the network topology.