The 4km line is expected to open by mid-2018 and construction costs are projected to be $US 124m, $US 55m of which will come from the US Federal Transit Administration.

In a separate vote, the council also approved the creation of a local tax district at the eastern end of Michigan Street which is expected to generate $US 31m towards the line's operating costs, which are forecast to be $US 3.2m per year.

Last December the city's Zoning, Neighborhoods and Development Committee voted to eventually extend the line to 7.4km, adding a branch towards Lake Michigan and the Couture development project, a proposed 44-storey apartment building.