Baltimore County marked the start of work Thursday on a long-delayed library and community college facility in Owings Mills — construction designed to jump-start a billion-dollar project that includes homes, stores and offices.

Promoted as an economic engine, the project near the Metro station was proposed in 1998 as a "Main Street" hub where residents would live, shop and play. But development got only as far as the massive parking garage, built in 2007, that overlooks Interstate 795.

But with construction on the community college and library starting this week, there are great expectations once again — and some lingering concerns.

"I'm very thrilled that it's getting under way, but I do recognize the economic challenges of launching the additional growth that was initially envisioned," said George Harman, president of the Reisterstown-Owings Mills-Glyndon Coordinating Council.

A $30 million, six-story building will house the largest branch of the Baltimore County Public Library and a new center for the Community College of Baltimore County — "the centerpiece" of the project, county officials said. That building is scheduiled for completion in winter 2013.

The larger development will include shops and restaurants, 500 housing units and 1 million square feet of office space.

The mood was buoyant at Thursday's groundbreaking, as County Executive Kevin Kamenetz credited county employees and former county executives with helping to keep the project alive. He also expressed appreciation to area residents for their patience and confidence.

"They have never stopped fighting for this Metro Centre," he said.

The concept of a town center development for Owings Mills arose more than three decades ago. County planners wanted to create a lake, surrounded by a mix of apartments and houses, as well as a library, mall and tree-lined boulevards.

But there were setbacks. The county could not get federal approval to dam Red Run and build the lake, and officials haggled for years over the cost of the library-community college building. Owings Mills Mall has had troubles, too.

"Owings Mills has long looked for a kind of community hub around which to develop or congregate," said Brian Ditto, executive director of the Reisterstown-Owings Mills-Glyndon Chamber of Commerce. "I see it as a meeting place for people in Owings Mills … that focal point."

Once the 2,900-space garage at the Metro station opened in August 2007, construction at the site came to a virtual halt, delayed by changing developers and legal wrangling.

The original developer, designated in 2000 to take on the whole project, backed out a year later amid an economic downturn. Owings Mills Transit LLC then took over, and the county agreed to build the community college center and library building on its own.

Ditto said the library and community college will be most welcome. Residents now go to the Pikesville, Randallstown and Reisterstown library branches, and the growth of Stevenson University shows that a larger community college would be beneficial, he said.

CCBC has outgrown its current Owings Mills space, which has 19 classrooms and little room for advising, tutoring and testing, President Sandra Kurtinitis said. The new center will have 27 classrooms, more computer and science laboratories, and space for a bookstore.

"If this didn't happen," Kurtinitis said, "we would have to be back on the drawing board, trying to figure out what we could do to increase the size of our facility there."

In a statement, developer Howard Brown with Owings Mills Transit called the start of construction a "major milestone in moving the Metro Centre project forward."

"Once the infrastructure for the library and college building has been completed," Brown said, "we will turn our attention to the next phase of the development, the Town Center, with a lively mix of shops, offices, a hotel and apartments."

Jerome Davis, who lives near the site, said the project's snags didn't diminish his excitement over its potential to raise home values and improve the local economy.

"Essentially what they are doing is placing people back in that area," said Davis. "Development is a long process, and you're really planning for the future."