The Metropolitan Council on Wednesday awarded a $118 million contract to Siemens to design 27 light-rail cars for the Southwest Light Rail Project.

Construction on the 14-mile line from downtown Minneapolis to Eden Prairie is expected to begin next year and cost $1.858 billion. The Federal Transit Administration is expected to contribute $928.5 million to the project, which will feature 15 stations and open in 2021.

The council's action on Wednesday authorizes the German-based firm to begin engineering cars that will be "improved versions of the Green Line cars, including improvements for users of wheelchairs and passenger with disabilities," the council said.

Production of the light rail vehicles will begin in early spring 2018 after the Met Council awards the second stage of the contract to build the cars, which will be able to be paired with cars currently in service on the Green Line.

Awarding the contract now will help keep costs down and allow enough time to produce and deliver the vehicles in time to do several months of testing before revenue service begins, the council said.

The total contract price is 5 percent lower than the lowest cost estimate and is included in the $1.858 billion cost for the total project, the council said.

“While this step forward is a technical one, it embodies the planning and work that has gone into SWLRT,” said Met Council Chair Adam Duininck. “As we seek to continue investing and building out our regional transit network, it is critical we find opportunities like these for future cost savings in operations and maintenance.”

The contract also includes the option for the Council to purchase an additional 50 vehicles to meet anticipated needs for the Blue Line Extension LRT project, should funding sources be identified. The Blue Line Extension is about nine months behind SWLRT in terms of its level of design. It would run from downtown Minneapolis to Brooklyn Park.