[4] Tunnels of Line 15 are up to 38 metres (125 ft) underground, making them the deepest in Beijing's subway system.

[5] A journey on a local all stop train from Fengbo to Qinghuadongluxikou station takes about 60 minutes.

New CIEC holds the annual Beijing International Automotive Exhibition, which attracted 800,000 visitors in 2012.

[7] [5][8] During planning of Line 15, the eastern terminus was moved from Fuqian Jie[10][11] to the east bank of the Chaobai River.

[2] According to the construction schedule in 2009, the easternmost Shunyi section of Phase I (18.5 km or 11.5 mi in length with seven stations) would be opened first on December 30, 2011.

In April 2009, Phase II plans showed the western half of Line 15 running from Xiyuan Station in Haidian District, through the campus of Tsinghua University, Zhongguancun, and the Olympic Green, and joining Phase I at Wangjing West.