More than 20 years of planning, some of it in fits and starts, led to a gathering of about 100 transit supporters under gray skies Friday afternoon to celebrate the upcoming construction of the $2 billion Southwest light-rail line.

The mood at the project’s frigid groundbreaking ceremony in Hopkins was festive and one of palpable relief. Southwest — the largest public works project in state history — has long been plagued with budget woes, delays and legal challenges, some of which still linger.

“We did it!” exclaimed Alene Tchourumoff, outgoing chair of the Metropolitan Council, which will build and operate the transit line linking downtown Minneapolis to Eden Prairie. A whoop rose up from the shivering crowd.

Elected officials and others lauded the promise of the state’s third light-rail line, saying enhanced transit will connect residents with jobs, reduce highway congestion and prompt economic development. Yet several acknowledged how difficult the decadeslong process has been.

“I’m starting to believe this is real,” said Hennepin County Board Chair Jan Callison. “Two things cannot be overstated: how hard this was and how important it is.”

An extension of the existing Green Line, the nearly 15-mile light-rail line will have 16 stations in Minneapolis, St. Louis Park, Hopkins, Minnetonka and Eden Prairie. Service is expected to begin in 2023, with weekday ridership averaging about 34,000, according to the Met Council.

“Residents will be able to take the train to U.S. Bank Stadium and watch the Vikings beat the Packers — again,” said U.S. Sen. Amy Klobuchar, D-Minn. The mitten-wearing crowd applauded.

Southwest cleared a critical hurdle last month when the Federal Transit Administration (FTA) notified the Met Council that it could begin spending local money to start the project — with the expectation that federal funds will be available later for reimbursement. The federal government is expected to pitch in $929 million toward the project.

The news prompted the Met Council to award a $799 million construction bid to a joint venture, Lunda/C.S. McCrossan — the lone remaining bidder in a process that dragged on for more than a year.

Early construction is expected to begin this winter and last through 2022, creating some 7,500 construction jobs with an estimated $350 million payroll.

While the go-ahead from the federal government jump-started the project, a Nov. 14 letter from the FTA to the Met Council said it “does not constitute an FTA commitment that future federal dollars will be approved for this project.” It’s common for agencies to start construction on transit projects after receiving such letters.

Transportation for America, a Washington, D.C.-based advocacy group, notes the U.S. Department of Transportation is sitting on about $1.4 billion for transit projects nationwide, including Southwest and the proposed Bottineau Blue Line light rail. Earlier this week, the FTA awarded $74 million to the Orange Line bus-rapid transit project connecting Minneapolis to Burnsville.

Though the mood Friday was celebratory, critics contend large, expensive light-rail projects like Southwest are a waste of taxpayer dollars.

“Why would we invest billions in LRT infrastructure when the country is on the edge of a revolution in transportation?” said Kim Crockett, vice president of the Center of the American Experiment, a Golden Valley-based conservative think tank. “Minnesota will be stuck paying for old technology while smarter metro areas adopt 21st-century options like ride-share, self-driving buses and cars and the use of ‘smart’ and dedicated lanes.”

But incoming Minnesota Attorney General Keith Ellison set aside criticism Friday.

“There were tough days, and there were many people who weren’t thrilled” with the Southwest project, he said. “I want to thank them. By challenging us, we made adjustments that made the project better.”