The Federal Railroad Administration changed course after Amtrak added structural repairs to 17 viaducts that support the proposed yard. The agency had initially determined the project qualified for a categorical exclusion, a finding that meant a more extensive environmental review was not expected to be necessary.

The project would redevelop about 60 acres of elevated land owned by Union Pacific Railroad along Canal Street between 33rd and 35th streets. A federal grant of nearly $600 million is slated to help convert the freight rail yard into an Amtrak maintenance facility and coach yard.

Amtrak says the new site would replace aging facilities constrained by limited space, improve rail service and create thousands of jobs. But Bridgeport residents have raised concerns about potential health risks and effects on families living nearby. Gov. JB Pritzker’s office has also argued that the proposal differs substantially from the project the state originally supported, calling it a “bait and switch.”

U.S. Sens. Dick Durbin and Tammy Duckworth welcomed the federal review in a joint statement Monday, saying it would allow community members to examine environmental studies and offer direct input. They also called on Amtrak and the developer to continue transparent discussions with residents.

The project still requires city approval. An Amtrak spokesperson said in August that the company had not yet submitted a site development plan to Chicago. Residents have previously said they were considering legal action to try to stop the project.