Ten Drives, Four TBMs Build Toronto Subway Extension

Arup and architect Grimshaw encountered a similar situation at the Vaughan Metropolitan Center, which is intended to serve as a major hub for transit-oriented development. Vaughan required some design changes based on extensive feedback from the region's stakeholders, notes Greville. "A future bus rapid-transit line will connect into the station from Highway 7 and have its own signature canopy at that stop, which marries well will the roof design for the station," he says.

In its $200-million contract, Carillion and its subcontractors dealt with an extremely high water table by building a bentonite cut-off wall, soldier piles, tie-backs and lagging, in addition to secant piles with walers and struts, says Graham Christie, Carillion construction vice president. The bentonite slurry "bathtub" is one meter thick and 20 ft deep, with the water table just one meter below the bottom slab, adds Dragomir Jevremovic, Spadina Link JV construction site manager. Since the site crosses over six-lane Highway 7, crews built a temporary bridge right over the cut-and-cover box, adds Jevremovic.

Before Vaughan becomes the northernmost stop on the new line, it will be the site of the final breakthrough for Yorkie and Torkie. Whether they emerge from their dual drives in a tie remains to be seen.

Aileen Cho, ENR's senior transportation editor, is a native of Los Angeles and recovering New Yorker. She studied English and theater at Occidental College, where a reporter teaching the one existing journalism course encouraged her to apply for the LA Times Minority Editing Training Program. Her journalism training led to her first stories about transportation, working as a cub reporter with the Greenwich Time. Her work has appeared in the Los Angeles Times and New York Times. Many of her experiences with engineers and contractors have inspired material for her alternative theater productions way, way off Broadway. For ENR, Aileen has traveled the world, clambering over bridges in China, touring an airport in Abu Dhabi and descending into dark subway tunnels in New York City. She is a regular at transportation conferences, where she finds that airport and mass transit engineers really know how to have fun. Aileen is always eager to hop on another flight because there are so many interesting projects and people, and she gets tired of throwing her cats off her computer in her home office in Long Beach, California. She is a very conflicted Mets/Dodgers fan.

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