Hierarchical structure in the world's largest high-speed rail network.

Sheng Wei,Shuqing N Teng,Xuejiao Yang,Haitao Ma,Maosong Liu,Jiangang Xu,Chi Xu,Zheng Y X Huang,Da Shen,Hui-Jia Li,Xia-Li Luan,Luc Berthouze

doi:10.1371/journal.pone.0211052

Abstract

Presently, China has the largest high-speed rail (HSR) system in the world. However, our understanding of the network structure of the world’s largest HSR system remains largely incomplete due to the limited data available. In this study, a publicly available data source, namely, information from a ticketing website, was used to collect an exhaustive dataset on the stations and routes within the Chinese HSR system. The dataset included all 704 HSR stations that had been built as of June, 2016. A classical set of frequently used metrics based on complex network theory were analyzed, including degree centrality, betweenness centrality, and closeness centrality. The frequency distributions of all three metrics demonstrated highly consistent bimodal-like patterns, suggesting that the Chinese HSR network consists of two distinct regimes. The results indicate that the Chinese HSR system has a hierarchical structure, rather than a scale-free structure as has been commonly observed. To the best of our knowledge, such a network structure has not been found in other railway systems, or in transportation systems in general. Follow-up studies are needed to reveal the formation mechanisms of this hierarchical network structure.

Highlights

While the mobile trajectories of human beings can vary greatly from person to person, strong regularities in collective human mobile patterns often arise as fascinating emergent properties in social systems [1,2]
The maximum train speed of the Chinese high-speed rail (HSR) is above 350 km per hour, enabling passengers to travel across the major part of mainland China within half a day
One possible explanation of such bimodal-like patterns is that the Chinese HSR system consists of two distinct regimes

Summary

Introduction

While the mobile trajectories of human beings can vary greatly from person to person, strong regularities in collective human mobile patterns often arise as fascinating emergent properties in social systems [1,2]. Previous studies on nationwide railway networks (e.g., Indian, Polish, Swiss, Japanese, and Chinese railway systems) have suggested that they have exponential or power-law-like degree distributions [14,15].

Results

Conclusion