Dive summary:

• Wanting to speed construction of a $110 million station in Seattle's light-rail network, Turner Construction came up with a sort of -ship-in-a-bottle technique that will allow it to pour concrete for underground portions of the station 40 feet at a time.
• The process involves sending a steel truss system into the tunnel, then expanding it to provide a framework for pouring 40 linear feet of concrete as well as circulating cool water to help the concrete cure more quickly.
• The truss system is then retracted to its original dimensions and moved ahead and re-expanded for the next section.

From the article:

To speed construction of the $110 million Capitol Hill Station light-rail station in Seattle, general contractor Turner Construction will use an unusual temporary framing method....