SAN FRANCISCO (KCBS) – Workers started pouring the foundation for San Francisco’s new Transbay Transit Center on Thursday, the latest milestone in the transformation of the Bay Area’s transportation landscape.

The giant Putzmeister concrete pumping machines began filling the vast six-story underground cavity at First and Mission streets, where the new Transbay Center will stand.

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“We’re going to be pouring 142,000 cubic yards of concrete, which is the equivalent of 30 Olympic-size swimming pools,” said Maria Ayerdi-Kaplan, head of the Transbay Joint Powers Authority.

She was joined by House Democratic leader Nancy Pelosi and San Francisco Mayor Ed Lee.

“This transit center will become a critical anchor for economic development and jobs,” Lee said. “After the thousands of jobs that the construction workers will have, there will be 27,000 permanent jobs.”

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Eleven different transit systems, including buses and eventually, high-speed rail, are expected to come together at what’s already being called “the Grand Central Station of the West.”

Workers on Thursday showed also off the 100,000 year old bay clay, left from the last Ice Age, they had to dig through to lay the foundation.

The Transbay Transit Center is expected to be completed in 2017.

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