Zhu et al. (2010) study residual deformation laws and a model of the permafrost
subgrade under train traffic, based on dynamic triaxial tests at low temperature of
the frozen clay from the Beiluhe permafrost subgrade along the Qinghai–Tibet
Railway (QTR). Wang et al. (2009) analyze the expansion of China’s railway
network, the evolution of its spatial accessibility, and the impacts on economic
growth and urban systems over a time span of about one century (1906–2000).
Their study indicates that railway network expansion has significantly improved
economic development and heavily influenced the formation of Chinese urban
systems.