CHICAGO (CBS) — Aldermen are expected to take a crucial vote Thursday on the massive Lincoln Yards development project, as the City Council Zoning Committee debates whether to approve a controversial plan that would change the landscape of the North and Northwest sides.

Opponents of the $6 billion project gathered at City Hall on Thursday to voice their frustration with the approval process. They said there are a lot of unanswered questions, and they want to see a final plan for Lincoln Yards before it moves forward.

The Lincoln Yards project would redevelop more than 50 acres of largely industrial land along the North Branch of the Chicago River, between Bucktown and Lincoln Park.

Developers would add 6,000 new residential units, public transit upgrades, new bridges, an extension of the popular 606 trail, and new parks. It would create some 12 million square feet of new buildings, including skyscrapers as high as 500 feet.

Earlier this week, developer Sterling Bay doubled the number of affordable housing units that would be built on-site to 600, but a coalition of groups opposing the project said there’s still no information on whether those units will be family-sized.

Opponents also argued the units only would be affordable to families at 60 percent of the area median income, something they said is still out of reach for Chicagoans facing displacement. They want to see a final plan before aldermen approve $1.3 billion in tax increment financing to fund infrastructure improvements as part of the project.

“The $1.3 billion is not an investment. It is something that will be put on the head of every homeowner in the city to make up the property tax deficit. It is fiscally irresponsible. It is a rush job put out by an outgoing mayor, and we need to stop it,” said Andre Vasquez, a candidate for alderman in the 40th Ward.

The Zoning Committee plans to vote on the project on Thursday. A full City Council vote could follow as soon as next week.

Both candidates for mayor have called on the City Council to hold off on a final decision until a new mayor and new aldermen are sworn in.