The number of domestic home bored subway station "runner"

187 m long, 21 meters wide, 20 meters high, so much did not see a pillar of underground space, excavators, construction vehicles which are so small, it is the reporter recently in Dalian, Xi'an Road area an underground subway station see the scene. It is reported that such a single-arch span of its column-free structure in the rare large, open ...The number of domestic home bored subway station "runner"