"We're celebrating the first bus to come into the Salesforce Transit Center," said Chris Peeples, a 20-year member of the AC Transit board of directors. "It's an O bus from Alameda. The last bus out on August 7, 2010, was an O bus at seven minutes after midnight. I was on that one, too."

Paul Marcelin, a longtime tech worker who lives in Alameda, was also on that last bus out of the Transbay Terminal. He says he doesn't drive, has long depended on public transportation, and that the long-awaited completion of the new terminal represents the fulfillment of a promise to commuters like him.

"This is the way we get around," Marcelin said. "Especially as an Alameda resident -- we don't have BART, so the transbay bus is a lifeline for us. I really support it, and I'm very excited to see this new terminal."

Victoria Wake, a transit activist who campaigned for years to save the old Transbay Terminal and later to make sure the terminal property was preserved for bus and rail service, got on the O as the bus made its way across Alameda.

She says she loved the old building, which had been neglected for years and was demolished after its 2010 closure, and the history and the aesthetic it represented.

"I would have preferred that some creative architects and engineers came up with way to improve it, to renovate it, and keep the 1930s era of it," Wake said.

A long time AC Transit rider, she, too. was on that last run out of the old terminal.

"We made a banner, and there were a lot of us," Wake said. "We were smiling because we were together, but it was kind of sad because the terminal was coming down."

The new terminal's biggest plus, she says: Restoring the old terminal's ramps off of and back onto the Bay Bridge -- something expected to speed up commutes and, perhaps, ease traffic congestion on surface streets around the temporary transbay bus stop at Folsom and Beale streets.

Once Sunday's first O bus arrived at the new transit center, to the cheers of dozens of AC Transit workers who had gathered for the predawn arrival, board member Chris Peeples said what's special about the new facility is its future potential.

"We're inaugurating this gorgeous new transit terminal, which will some day have trains in the basement, first Caltrain and then, if high-speed rail ever gets finished, it will terminate up here," Peeples said. "So it's gonna become a center of transit for pretty much the whole West Coast, but particularly the Bay Area."