Mercury News » The Valley Transportation Authority, which is building the tunnel, has recommended a single 45-foot diameter subway bore with two tracks and a dividing wall between tracks. The authority argues the design will be cheaper and less disruptive during construction. But the so-called single-bore option has not been widely tested and design studies are only 20 percent complete, so the full costs aren’t clear.
Michelle2017-10-12T09:40:46-08:00October 2nd, 2017|California, Design-Build, Highways, Metro Rail / Transit|