Dakota County is seeking $2.2 million in state money for two tunnels that planners say will safely complete a key link for pedestrians and bicyclists on the Mississippi River Regional Trail.

The county reached agreement with the Union Pacific Railroad to build the tunnels in Rosemount for about $6.5 million, according to Commissioner Tom Egan.

The tunnels would let bikers and hikers pass beneath the railroad tracks on the trail, which runs between Hastings and St. Paul.

The county plans to cover much of the cost with $1.4 million in federal money and local funds. Planners are hoping the project appears on a bonding bill this legislative session to help fund the remainder. Construction would then likely begin in 2017, planners say.

"It's a real safety issue," Egan said, adding that it's the county's second-highest priority behind a $6 million request to upgrade the Byllesby Dam near Cannon Falls. "We felt it was critical to be able to cross the tracks as quickly and safely as possible."

The roughly 1.7-mile stretch of incomplete trail is near an industrial site on the river that draws both truck and rail traffic. Without the tunnels, bikers or pedestrians can't travel a continuous route on the trail, but it was difficult to find a solution, Egan said.

The county conducted studies on above- or below-grade options and determined that tunnels were the best plan to patch the gap.

"It's taken some time to find a safe route through the segment," said Steve Sullivan, the county parks director.

"The county has a responsibility for this last gap, and it's been making a strong effort to get it funded through the legislative request."

The county's most recent addition to the trail is a 4.6-mile section overlooking the river in Spring Lake Park Reserve. Construction began last spring and continues this year.