The simmering legal battle over the $1.77 billion Southwest light-rail line bubbled back into public view this week as opponents sought information from the Metropolitan Council on how the state’s most expensive transit project was planned and has been carried out so far.

A Minneapolis nonprofit group called the Lakes and Parks Alliance (LPA) filed suit in U.S. District Court in 2014 against the regional planning agency, claiming it violated federal environmental laws in selecting the current route for the project. The controversial line will link downtown Minneapolis to Eden Prairie, passing through St. Louis Park, Hopkins and Minnetonka along the way.

The LPA has requested a sweeping list of documents from the Met Council related to the planning and engineering of the project, including the names of people involved, possible alternative routes considered, and communiqués with elected and government officials, according to records filed in federal court this week.

If successful, the group plans to use the information as ammunition to bolster its ongoing legal claim against the Met Council.

In response, Met Council attorneys filed for a protective order that would preclude it from releasing the documents, arguing it could prove to be “unfair, inefficient and unnecessary,” court records state. “There has been no allegation, let alone a strong showing, of bad faith or improper behavior and, therefore, there is no basis for the court to extend its inquiry beyond the forthcoming administrative record in this case.”

The matter will be considered by Magistrate Judge Steven Rau at a hearing on Jan. 11.

A key sticking point for the LPA is the project’s pathway through the Kenilworth corridor in Minneapolis, a recreation area popular with bicyclists and pedestrians near Lake of the Isles and Cedar Lake.

“It appears the Met Council is stonewalling,” said LPA spokeswoman Mary Pattock. “It makes us wonder what they have to hide.”

Met Council spokeswoman Kate Brickman countered: “The Council follows state and federal law as well as applicable judicial rulings when releasing documents. The Council’s objection to LPA’s request to engage in discovery is purely a procedural motion.”

U.S. District Judge John Tunheim declined to dismiss the suit last summer, and said a final ruling would be premature. “When the record is more adequately developed, the court will again consider a summary judgment,” he wrote, noting, “This action involves complex legal issues and an evolving factual record.”

After project costs ballooned by $341 million last spring, the Met Council cut $250 million from the budget; some cities along the line, as well as Hennepin County and its railroad authority, agreed to pitch in more money and land. A federal environmental review is expected to wrap up next summer — a critical step needed to win $827 million from the Federal Transit Administration.

Metro Transit spokeswoman Laura Baenen said in a statement, “This type of environmental claim should be based on a review of the official record prepared by the agency after the [environmental review] is complete. That has not yet occurred because the environmental review of the proposed Southwest LRT Project is ongoing.”

Recently, the U.S. Congress included $5 million for the project in the 2016 federal omnibus appropriation. The Met Council still needs to nail down $135 million in state money for the project, but the future of that funding is unclear, since some legislators oppose light-rail transit. Still, the Met Council expects the line, actually an extension of the current Green Line, to begin passenger service in 2020.

Court records also indicate that both sides have engaged in settlement talks. But, as Baenen noted, “the federal rules of civil procedure require parties to engage in certain discussions before filing a motion. The Council and LPA participated in such discussions before filing this motion.”