A tunnel boring machine emerged in an open pit after digging through a tunnel under the Taihu Lake on Jan 6, 2015.
The 730-meter-long tunnel is built for Metro Line 4 and will connect Huagang Road Station and West Jiangling Road Station.
Metro officials said the two stations are 2,786 meters apart, the longest distance between two subway stations in Suzhou, compared with an average of 1,200 to 1,300 meters.
They said that more than 70 percent of this stretch of Metro Line 4 is under water in the eastern part of the lake.
