Beijing News said that Beijing Subway Line 12 is set to open to the public in 2020. The new line will cut through the North Third Ring Road from Sijiqing Qiao to Guanzhuang, covering a total length of 29.3km.
This is how the line will run across the city:
15 stations will be transfer stations among all the 21 stations, allowing for transfers to Lines 3 (still under construction), 4, 5, 8, 10, 13, 14, 16 (still under construction), 17 (still under construction), 19 (still under construction), the Changping Line, and the Pinggu Line. What's more, within a 100-meters- walk,passengers can transfer at the majority of the new stations.
The new stations (from west to east) include the following:
Trains on the new line will travel at a speed of 80km per hour, and construction at Suzhou Qiao has already started. Since the trains will pass through 34 flyovers, adding a further complication to the construction, it is estimated that the entire line won't be completed and operational until 2020.