The posted ground rules made it clear this was no ordinary neighborhood meeting, but a prelude to a decisive and divisive vote on the Twin Cities' biggest transit project.

"Show respect for others' viewpoints," read one rule for the meeting in the Kenwood section of Minneapolis, where residents questioned plans for the project. "Metro Transit police are present for everyone's safety."

The plan to put the Southwest Corridor light-rail line in tunnels straddling a water channel between two Minneapolis lakes is expected to be presented Wednesday for approval to the Metropolitan Council, a group of policymakers overseeing the project. Their vote marks the culmination of years of work on a nearly 15-mile route that has swollen in price, pitted residents and officials of Minneapolis and St. Louis Park against one another and provoked rare dissension on the Met Council itself.

"I can't think of another project where we've had this kind of acrimony," said Metropolitan Council member Gary Cunningham, who plans on voting against the tunnels. He accused the Met Council chief and administration of pushing the plan forward without answering important questions about its impact on the environment or exploring other options.

"I've never seen this kind of railroading," Cunningham said.

At least one other council member is expected to join him in voting no. But the Met Council's 17 members usually take their cues from the professional staff that designed the plan and are expected to approve it, setting the stage for a bitter fight over the next few months with the city of Minneapolis. Minneapolis Mayor R.T. Rybak and several City Council members have come out against the plan.

The agency must ask for the city's consent, but it hasn't ruled out trying to move forward without it. A refusal by Minneapolis to approve the tunnels would move the project into uncharted legal and political territory, delaying and possibly jeopardizing it.

The tunnels would bring the total cost of the project to $1.55 billion, up from $1.25 billion earlier this year. To afford them, planners trimmed a mile and two stations off the line.

The Southwest Corridor light rail would run from downtown Minneapolis to Eden Prairie, passing through three other suburbs. Supporters hope to finish designs, secure additional funding and begin construction in 2015.

Freight vs. light rail

The plan involves digging nearly half-mile-long tunnels on either side of the water channel between Lake of the Isles and Cedar Lake in the Kenilworth corridor of Minneapolis, an area popular with bikers and canoeists. The trains would climb out of the tunnels and cross a bridge over the channel in a 360-yard stretch where they would be exposed for roughly 20 seconds.

The $160 million tunnel option would involve removing 1,000 trees but was deemed less disruptive than rerouting the freight trains from the Kenilworth corridor to St. Louis Park to make room for the light rail. That $200 million option was discarded by a panel of metro leaders last week after stiff opposition from St. Louis Park and some of its residents to putting the freight on two-story berms that a railroad said were needed to smooth out grades. The reroute would have required removing 30 properties in the suburb.

If the freight were rerouted, the light rail would be built at ground level through the entire Kenilworth corridor next to the recreation trails.

Met Council staff engineers and council chair Susan Haigh concluded that tunnels are better because they keep existing freight traffic in the corridor while hiding the future light rail most of the way. About 220 light-rail trains would use the corridor daily along with several freight trains that currently run through it. No homes would be removed. The Kenilworth bike and pedestrian trails would be moved to nearby streets during construction but later restored to the corridor.

"Our solution is the tunnels, because they preserve the Kenilworth trail as best we can in the condition that it's in," said Council Member Jennifer Munt, who will vote for the plan. "It's a good compromise."

But the tunnel plan faces opposition from some in Minneapolis who say the trains surface for too long near the channel and who distrust assurances that bike trails and lakes will be preserved. Rybak and several City Council members want the Met Council to explore more options for rerouting the freight to St. Louis Park. They say planners violated guarantees to move the freight out of the Kenilworth corridor in exchange for locating the light rail there.

Kenwood residents held signs reading, "If the freight stays, LRT goes," at the Met Council's open house Thursday. Others pored over giant engineering maps laid out on tables and quizzed agency planners and public relations employees about details. Not everyone opposed the tunnels.

"I love the plan," said Cheryl LaRue, who owns a townhouse along the freight tracks in the corridor, explaining that she wouldn't mind continuing freight traffic as long as the light rail is mostly hidden. LaRue said city officials opposing the tunnels may not be in sync with many residents. "I've lost my patience with them," she said.

Agency dissenters

Met Council members Cunningham and Adam Duininck, who chairs its transportation committee and also opposes the plan, say their agency should slow down to explore other freight reroute alternatives to the tunnels. Representing sections of Minneapolis outside the Kenilworth corridor, they also call for more environmental studies to safeguard the lakes.

Cunningham is married to Minneapolis City Council Member Betsy Hodges, a candidate for mayor who also opposes the tunnels. He complained that Haigh was "pushing the project forward without the work that was agreed to being completed."

While acknowledging there were enough votes on the Met Council to approve the tunnel plan, Cunningham said it risks being rejected by Minneapolis.

"I'm trying to understand what the strategy is," he said.

Haigh was unavailable for reaction Friday.

Collision course

If the Met Council approves the tunnel plan Wednesday, the Southwest Corridor project will be sent to the city of Minneapolis for its consent. A state statute lays out a process that might initially take 75 days, during which Minneapolis could reject the plan and suggest changes that would make it acceptable. The Met Council then would have additional time to respond.

"It anticipates that there is going to be a meeting of the minds," said Tom Johnson, a former Hennepin County attorney who is representing some Kenilworth residents opposed to the tunnels. "And you keep this process going until that happens." The statute allows for repeated rounds of give-and-take.

Johnson said just two rounds could take "at least four months … I bet you're closer to six months."

The process is mostly untested. No city withheld consent from plans for the Central Corridor or Hiawatha light-rail projects. Haigh has not said whether she would try to push forward with a plan even if Minneapolis refused to give consent.

But one key legislator said political reality makes that a bad strategy.

"You really do need to line up political support along the corridor, particularly from the region's largest city," said Sen. Scott Dibble, DFL-Minneapolis, chair of a Senate transportation committee.

Pat Doyle • 612-673-4504