Do railways improve territorial cohesion of the Tibetan Plateau? A case study of the Qinghai-Tibet Railway

Over the last 60 years, the Qinghai-Tibet Railway has gradually expanded its coverage. However, the possible impact of railway construction on territorial cohesion of Tibetan Plateau (TP) is unknown. By combining the railway development of TP in different periods, this study constructed different scenarios and used an accessibility indicator to reveal the changes in territorial cohesion. First, railway construction has prompted an improvement in the overall accessibility level of TP and has created a notable spillover effect. TP's own potential demonstrates a rapidly increasing trend, whereas the internal and external accessibility benefits brought by railways to TP are gradually decreasing. Second, TP's own potential has a negative impact on territorial cohesion. The Golmud-Lhasa section of trans-provincial Qinghai-Tibet Railway is more conducive to promoting territorial cohesion between TP and the outside areas, whereas the non-trans-provincial railway can better promote territorial cohesion within TP. Third, considerable differences exist in the spatial impact of the railway on the internal and external cohesion of TP. Internal cohesion is mainly reflected in the formation of high-accessibility corridors between cities along the railway, and external cohesion is affected by the expansion of the highway and railway connecting the outside part to the interior of the plateau.