As construction begins on the Southwest light-rail line next week, the fate of the Twin Cities’ fourth light-rail project, the Bottineau Blue Line, remains uncertain.

The $1.5 billion Bottineau line is slated to connect downtown Minneapolis with Brooklyn Park, traveling through north Minneapolis, Robbinsdale, Golden Valley and Crystal. Service is expected to begin in 2024.

But a dispute continues to simmer over plans for light-rail trains to share about 8 miles of the 13-mile route with freight trains on property owned by BNSF Railway — a scenario that requires approval from the Texas-based railroad giant. Over the past four years, BNSF has been consistent in its opposition to the plan.

“Our position hasn’t changed,” said spokeswoman Amy McBeth. “We’re not proceeding with any discussion of passenger rail in this corridor on our property.”

A group of local transit planners met with BNSF representatives recently and a “robust discussion” ensued, according to the Metropolitan Council, which will build and operate the Bottineau project.

When asked if Bottineau is still moving forward, Met Council Spokeswoman Kate Brickman said the project “continues to be a priority” for the regional planning body and Hennepin County.

But Bottineau’s key citizen and business advisory committees haven’t met since November. Opening day has been pushed back — as recently as two years ago, service was slated to begin in 2021; now it’s 2024. Project Manager Dan Soler, who worked on the Green Line, departed for a job with Hennepin County.

It’s also unclear whether BNSF will require that a crash-protection wall separate freight and light-rail trains along Bottineau’s shared corridor. BNSF requested a wall along a shorter shared stretch on the Southwest route west of Target Field — adding $20 million to the project.

Brickman said “there have been no discussions of a wall” with the railroad; BNSF declined to comment.

Some also worry the freight and light-rail trains traveling alongside each other is dangerous.

Claire Ruebeck, of the Twin Cities group Citizens Acting for Rail Safety, said freight rail carrying high-volume oil and ethanol shipments “coupled [with] glaring liability insurance gaps and weak safety regulation means that co-location can create dangerous and unnecessary risk.”

The Federal Transit Administration (FTA) has made it clear a deal with the railroad needs to be nailed down before a $753 million grant application for Bottineau moves forward. So far, about $124 million in state and local money has been spent on the project.

In an e-mail, the FTA said that last year the council “claimed in communications with FTA that the project is essentially on hold due to railroad right of way issues with BNSF.”

At the recent meeting with Met Council and Hennepin County staff, BNSF continued “to have numerous serious concerns about co-locating freight rail and light rail in their corridor,” Brickman said. While the railroad’s stance “was not unexpected,” she said the council now has “more detailed information to consider than we had in the past.”

The council and Hennepin County “are in active conversations” about the railroad’s guidance and considering next steps, she said.

“We’re working with the railroad to understand their issues,” said Hennepin County Commissioner Mike Opat, whose district encompasses the Bottineau corridor. “We need to get the railroad to the table in earnest. If the federal government reneges on the state and local governments [for funding] then we will have a crisis.”

But Brooklyn Park Mayor Jeffrey Lunde said the fact that Southwest appears to be moving forward bodes well for Bottineau.

“The Blue Line was never going to jump ahead [of Southwest],” he said. “All of these lines run in a sequence.”

The Blue Line Coalition, a group of elected officials from Minneapolis and suburban communities along the Bottineau route, recently traveled to Washington, D.C., to rally support for the project among Minnesota’s congressional delegation and with the FTA.

“The message from D.C. was, ‘You’ve come as far as you can go. Come back when you have the [BNSF] agreements,’ ” Lunde said. Given the specificity of that advice, “it seems like the process is moving forward.”