Research on the centrality of sea-rail intermodal transport network in the Yangtze River Delta region

From the perspective of the directional connection relationship between seaports and dry ports, this paper uses the 3 core seaports in the Yangtze River Delta region and the 55 dry ports that cooperate with them to construct a sea-rail intermodal transport network by applying the multilayer network theory. The centrality of the port before and after adding the sea-rail intermodal transport lines is analyzed by using the index of degree centrality, closeness centrality, betweenness centrality, eigenvector centrality, and integrated centrality. The results show that the addition of sea-rail intermodal transport lines has greatly improved the network centrality and importance of Ningbo Zhoushan Port and Shanghai Port, but the network centrality of Lianyungang Port has been improved to a lesser extent, which is consistent with the development of sea-rail intermodal transport in seaports. The addition of sea-rail intermodal transport lines not only enhances the direct capacity between seaports and dry ports but also weakens the transfer role of dry ports, which reduces the centrality of most dry ports.