From the Chinese-language version of the China Daily.  Indeed, yes, parts of it will become express-stops only and it will be the smaller stations that are skipped during morning and evening rush hours.

"Almost parallel to Subway Line 1, Beijing Subway Line 6 is a main artery crossing Beijing City from east to west. With a total length of 52 kilometers (32 miles), Line 6 is longer than any other line under operation or construction in Beijing. The construction of Line 6 is divided into three phases and the first phase has been completed. It runs from Haidian Wuluju in the west to Caofang in the east. Other sections from Wuzi University to Dongxiaoying and from Pingguoyuan to Tiancu are still under construction. It is said that all construction will be finished in 2015.

As planned, Line 6 is expected to have express sections. For instance, it will drop small stations in rush hours in order to reach the downtown area directly. The speed will reach as much as 80 to 100 kilometers per hour (40 to 62 miles per hour). This mode of transportation will be in operation after the implementation of phaseⅡ. At present, the line stops at all 20 stations."