A passenger takes a selfie in front of the first train departing from Qiaozhuang East Station in Tongzhou district to Beijing West Railway Station, June 20, 2019. Qiaozhuang East Station on the sub-center line went into operation Thursday. The sub-center line is one of Beijing's three suburban railways and links urban Beijing and sub-center Tongzhou. [Photo/IC]

Passengers take their seats on the first train to depart from Qiaozhuang East Station in Tongzhou sub-center to Beijing West Railway Station in western Beijing, June 20, 2019. [Photo/IC]

The first train bound for Beijing West Railway Station is ready to depart from Qiaozhuang East Station in Tongzhou district, Beijing, June 20, 2019. [Photo/IC]

A man takes photo of the train bound for Beijing West Railway Station from Qiaozhuang East Station in Tongzhou district, Beijing, June 20, 2019. [Photo/IC]

Passengers get off as a sub-center line train from Beijing West Railway Station arrives at Qiaozhuang East Station in Tongzhou district, Beijing, June 20, 2019. [Photo/VCG]