Gearing up for a possible legal fight over Southwest light rail, Minneapolis' Park Board voted Wednesday to seek advice from attorneys with transportation expertise.

The board asked Stinson Leonard Street to research their legal options under a section of the federal Department of Transportation Act that protects parkland. That section, known as "4(f)," requires that transportation projects have minimal impact on parklands unless there are no feasible and prudent alternatives.

Another group of private citizens has already filed a separate lawsuit over the line against the Metropolitan Council and Federal Transit Administration because the line was approved without an updated environmental impact statement -- due out early next year.

The $1.6 billion Southwest line would run from Eden Prairie to downtown Minneapolis, following an existing freight rail corridor through the city's prized Chain of Lakes. The board has previously expressed it's opposition to the shallow tunnel needed to squeeze freight rail, recreational trails and light rail through a pinch point near Cedar Lake (see full explanation below).

"I just don't believe you can build this thing and it's not going to impact those lakes," Commissioner Annie Young said through tears on Wednesday. "If nothing else, for seven generations. And the kids. It may seem like nothing now, but 50 years from now it's going to mean a lot."

The law firm is expected to update the board on October 1. Several commissioners said retaining their advice amounted to using heavy artillery after being ignored by project planners.

"We've really exhausted every polite avenue that we could to try and get across our concerns," said board President Liz Wielinski, saying the project will create the equivalent of "a freeway bridge" above the canal.

"This is like we're drawing a line in the sand," said Commissioner Meg Forney. "We have gotten the short end of the stick on numerous occasions….So I look at bringing on legal counsel as an investment for more future conversations, as well as this conversation."

Commissioner Brad Bourn expressed concern about the cost of the contract, $22,000, in relation to the amount of work the firm will do. The Park Board already has an in-house attorney.

But Young said money should not be the primary issue, citing citizens who have written in to offer their help. "They'll throw us a fundraiser. They'll do whatever," Young said. "We have a foundation that will help protect us. We have lots of resources outside of this system that will rise up and fight in this struggle."

Here is the section of the board's August 2013 resolution focusing on the shallow tunnel concerns. While two tunnels were under consideration when the resolution was passed, only one was included in the final plan.

Whereas, The shallow tunnel option would be constructed by open trenching, essentially removing all existing vegetation within the current trail corridor;

Whereas, MPRB, SWLRT project office and City of Minneapolis staff have recently had significant conversations about the shallow tunnel option and specifically about the crossing of the Kenilworth Channel and vegetation removal;

Whereas, The shallow tunnel option would construct a significant amount of infrastructure directly adjacent to and over the Kenilworth Channel including concrete portals, safety fencing or walls and widened bridge decks as necessary to bring the light rail back to grade and over the Channel;

Whereas, After deliberating on the SWLRT options, the MPRB believes the shallow tunnel option as currently proposed will permanently damage the recreational, cultural, and aesthetic experience of MPRB parklands and assets at a particularly fragile and critical location that would be overwhelmed by the proposed co-location of light rail and freight rail infrastructure;