Beijing underground cross-city railway

The Beijing underground cross-city railway is a short railway connection in Beijing. It connects the important transportation hubs Beijing railway station and Beijing West railway station. For the most part it is underground, in a section known as the Qiansanmen Tunnel. The speed limit is 120 km/h. It also connects lines from southern and western areas with lines from northeast China. The railway has a length span of 9.156 km (5.689 mi), and has been officially operational since March 20, 2015. It is used by conventional railway lines such as K7752 from Shijiazhuang to Chengde via Beijing West railway station and Beijing railway station, as well as the commuter rail Sub-Central line of the Beijing Suburban Railway, which started in December 2017.

Tunnel data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).