The Metropolitan Council on Wednesday formally approved a $1.5 billion cost estimate and updated plans for the light-rail line linking downtown Minneapolis to the northern suburbs, sending the project to Hennepin County and five corridor cities for their approval.

The council approved a list of last-minute additions, including a park-and-ride lot at the Golden Valley Road Station and a rebuilt intersection at Theodore Wirth Parkway and Golden Valley Road that includes trail connections.

The latest estimate, which works out to $1.496 billion, is a nudge above the $1.488 billion reported in October when a Met Council advisory committee learned that the price tag for the 13-mile line had gone up by nearly 50 percent from the initial estimate of $1 billion.

The Bottineau Blue Line extension would run between Target Field in downtown Minneapolis to Brooklyn Park. Other cities along the route are Golden Valley, Robbinsdale and Crystal.

Those cities and the county have until March 4 to approve the preliminary plan, according to state law. The goal is to have the light-rail line running by 2021.

Dan Soler, the project’s director, stressed at Wednesday’s meeting that the new $1.5 billion figure is still an estimate, not a budget. The cost could fluctuate as more of the project’s engineering is completed, he said.

“There is just 15 percent engineering done and a lot of unknowns. … The hope is it won’t change significantly,” Soler said.

The Met Council still must secure funding. Currently, the Federal Transit Administration is expected to pay 49 percent and the Counties Transit Improvement Board, 31 percent. Hennepin County and the state would split the 20 percent balance.

Metropolitan Council Chairman Adam Duininck applauded the council’s action Wednesday.

“The Blue Line Extension will connect thousands of residents throughout our region with jobs,” he said.

The tracks will be built down the middle of Olson Highway, parallel Bottineau Boulevard and eight miles of existing BNSF freight tracks, and then run down the middle of Broadway Avenue W.

The strategy of building alongside existing roadways and railroad tracks reduces the need to take private property, but it increases the cost of bridges and infrastructure needed to ensure that trains and vehicle traffic flow smoothly.

Plans call for constructing or rebuilding 13 road and rail bridges, along with a pedestrian walkway in Brooklyn Park. Original plans estimated the need for work or construction of six bridges, based on early engineering work.

Other add-ons include a Plymouth Avenue station to serve north Minneapolis and an increase in the number of light-rail cars from 26 to 28 to ensure that trains will run at 10-minute intervals. When installing the light-rail tracks, Metro Transit will reconstruct Hwy. 55 and move underground utilities.

The Met Council and the Hennepin County Board will hold a joint public hearing on the line next month at the county’s Central Library in downtown Minneapolis.

The price has also risen for the controversial Southwest light-rail line linking Minneapolis to Eden Prairie. Last spring, the Met Council said the cost of the Southwest line had increased by $341 million to nearly $2 billion. Since then, communities along the line have agreed to substantial cuts and contributed more local funds to keep the project afloat. The current cost estimate is $1.77 billion.