Eager to end a confrontation that could kill the region's biggest transit project, the agency in charge has agreed to hire a former federal magistrate as peacemaker to help settle its dispute with Minneapolis.

Initially reluctant to use a mediator, the Metropolitan Council bowed to Minneapolis' desire for an outsider to help broker negotiations over building the $1.68 billion Southwest Corridor light-rail project. City opposition to digging tunnels for the light-rail line in the Kenilworth corridor has threatened to halt the project as it approaches critical deadlines this summer.

The city and the Met Council chose Arthur Boylan, who helped negotiate an end to the NFL players lockout several years ago and who recently retired as chief magistrate judge in U.S. District Court in Minnesota. They picked Boylan after considering DFL fundraiser and former diplomat Sam Kaplan and former St. Paul Mayor George Latimer for the mission.

The decision to engage a mediator underscores the deep divide between the Met Council — the metro area's planning agency — and Minneapolis over the Southwest project.

"I think the judge coming in may be useful, it may not be," Minneapolis City Council Member Abdi Warsame said Wednesday. "Maybe we need a third party, somebody who can bring the two groups together to look at the bigger picture."

The Met Council must seek city consent before moving forward with the light-rail project, and the two sides will be discussing possible deals in the coming weeks. State law requires a city decision by July 14, and a board of Twin Cities counties that bankrolls transit projects has set a June 30 deadline.

"I haven't met with either side yet, where we could talk about the scope of the work I'll be asked to undertake," Boylan said Wednesday.

The Met Council and the city offered few details of his role. They said he would be working with both sides "over the coming months."

The full Met Council didn't vote to select a mediator but the decision was approved by its administration and council Chairwoman Susan Haigh, said Council Member Jim Brimeyer, who supports the idea. While the agency and the city stressed that it was a joint decision, Brimeyer said the push came from Minneapolis Mayor Betsy Hodges.

"The mayor really wanted it," Brimeyer said, recalling that three weeks ago a Hodges aide told him "the mayor would like a mediator to help us deal with this."

"There was some reluctance initially on our part to do that," Brimeyer said. "At that time I don't think Sue was in favor of it."

He said Met Council resistance stemmed from concerns that a third party wouldn't "understand all the nuances of this project."

The Southwest Corridor plan for running light rail through nearly a mile of tunnels in the Kenilworth corridor near bike trails and freight trains has been opposed by nearby residents as well as the City Council and Hodges. Some critics insist that the freight trains be moved, while others don't want the light-rail trains in the corridor. But the plan has the overwhelming support of officials from other cities along the nearly 16-mile line between downtown Minneapolis and Eden Prairie.

Some Met Council members earlier considered enlisting Kaplan, a former U.S. ambassador to Morocco and influential DFLer, as someone who might make peace between the agency and the city. But Boylan, who now runs his own mediation firm, emerged as the favorite candidate. He helped to settle the 2011 labor dispute between the NFL and its players.

"It took 29 days of mediations [each day going well into the evening] before that matter settled," Boylan said Wednesday. "And that was only after the parties were before the federal labor mediator in Washington, D.C., for weeks without success."