To handle more people expected to take light-rail and commuter trains to downtown Minneapolis in the years ahead, Hennepin County is proposing a large pedestrian plaza, elevated rail tracks and underground parking on the north side of Target Field.

The estimated cost of the so-called Interchange project is about $80 million, although project manager Ed Hunter said that figure needs further vetting.

The 2-acre plaza would provide room for more than 20,000 riders expected to be coming and going daily after the Central Corridor light-rail line reaches Target Field in 2014.

The project should get underway within two years, Hunter said, to ensure that it's done by the time Central Corridor trains begin running.

"Is it perfect? No. Will it get tweaked? Eventually," Hunter said of the plan, which he presented Friday to the Minnesota Ballpark Authority.

The county is paying for the design work, but planners hope most of the funding can be obtained through matching grants from the Federal Transit Administration.

Hennepin County Commissioner Peter McLaughlin, who chairs the county's Regional Railroad Authority, said the project is the next step in making Target Field one of the metro area's two major transportation hubs, along with Union Depot in St. Paul. The ballpark area includes the Northstar commuter line, a number of bus routes, a city-suburban bike trail and large parking garages.

"It's a big leap forward here," McLaughlin said.

The county's Environmental Services Building would have to be razed to make room for the project, which would be built next door to the county garbage burner. The site would include a parking structure below the plaza with 550 spaces and might also accommodate a future office building.

Hunter said the plan would create a better access point for the ballpark at 5th Street and 6th Avenue N. The corner would be built out as an approach to the new pedestrian plaza.

Tracks for the proposed Southwest and Bottineau light-rail lines would be built 35 feet above the corner, curling around the garbage burner site before connecting with the Hiawatha and Central Corridor tracks at the ballpark.

The area at 5th Street and 6th Avenue contains tracks on which light-rail cars are parked when not in use. Under the plan, those tracks would be moved west and wrap below N. 7th Street.

"We're starting to see that we can get all the [light-rail] trains into this place," McLaughlin said. "Using [garbage burner] land as layover space, I think that's brilliant."

Hunter said that the next steps include an environmental assessment of the project and a series of public meetings to get input and reaction.

Kevin Duchschere • 612-673-4455