A proposed concrete wall along a portion of the proposed $1.9 billion Southwest light-rail route in Minneapolis has drawn the ire of elected officials who want an additional environmental study done before the partition is built.

The $20 million wall was requested by BNSF Railway while it was in right-of-way negotiations with the Metropolitan Council, which will build and operate the 14½-mile line between downtown Minneapolis and Eden Prairie.

The regional planning body approved the construction of the mile-long wall between the Royalston Avenue/Farmers Market and Bryn Mawr stations last month, part of a broader agreement with BNSF.

The wall is expected to be about 10 feet high and 3 feet wide, and is intended to separate freight rail cars from light rail trains, both of which will share the corridor.

A letter sent Thursday to Met Council Chairwoman Alene Tchourumoff requesting additional study of the wall and its possible effects on the community was signed by Minneapolis Mayor Betsy Hodges, and Council Members Lisa Goodman, Kevin Reich, Lisa Bender and Cam Gordon. State Sen. Scott Dibble and Rep. Frank Hornstein, both DFL-Minneapolis, also signed the letter.

“We are surprised at the lack of information about the proposed barrier wall that has been provided to us,” the letter states. “We are also surprised about the lack of a public process and open community engagement about a subject that is important to our residents.”

In response, Tchourumoff said in a statement that Southwest’s planners will work with the city and the community “on the aesthetic design of the wall.”

She said the community outreach plan includes open houses, checking with neighborhoods such as Bryn Mawr, and consulting with the project’s Minneapolis landscape advisory group.

“The council shares the priority of protecting our environment,” Tchourumoff said. “We will of course comply with all state and federal laws to ensure adequate protection of our environmental resources, and intend to do all appropriate and necessary environmental work related to this wall.”

The Met Council will provide tours of the railroad trench beginning next week to discuss the potential impact of the wall.