A year ago when Boston’s Olympic hopes were still alive, Mayor Marty Walsh anointed Widett Circle as the site of the city’s next great neighborhood. Today, the state may need the land to park trains if it gets to expand South Station.

The prospect is not sitting well with the mayor, who is trying to persuade the state to look elsewhere.

“I am not excited about putting a train layover yard there,’’ Walsh said in an interview. “There is certainly a lot better use for that land.’’

For those of you who have already forgotten our Olympic dream, Widett was to be the home of a temporary stadium for the opening and closing ceremonies, and afterward an 8 million-square-foot complex with apartments, shops, and offices. Now the site of a food vendor market and other industrial businesses, Widett was slated to become a Back Bay for the 21st century, the biggest legacy of hosting the 2024 Summer Games.

Even though the bid collapsed last July, the Walsh administration continues to pursue the potential redevelopment of Widett, a prime site buffered by South Boston and the South End. At the same time, state transportation officials have identified Widett as one of the top locations to store trains.

The state is expected to make a recommendation in the spring as it finishes up a final environmental report for the $1.6 billion South Station project. In an interview, Transportation Secretary Stephanie Pollack said she is aware of the city’s concerns and has been talking with the mayor and the Boston Redevelopment Authority.

“Obviously Widett has become more interesting for other uses as well,’’ Pollack said. “We have told the city that we will continue that conversation before we make any final decisions.’’

Now some of you may be asking, what’s the big deal here? Didn’t the Olympic plan call for building over active rail lines with a deck that would support development on top?

Yes, that’s true, Walsh acknowledged, but he worries that the state plan may require an even bigger deck, and that could scare away potential developers.

“That would add costs to the project that I don’t know if anyone would be able to recoup,’’ Walsh said.

In addition to Widett, potential layover sites the state has been looking at include a portion of Beacon Park Yard in Allston, which is owned by Harvard University, and Readville Yard, which is owned by the Massachusetts Bay Transportation Authority. A draft report — filed in the fall of 2014 before Pollack became transportation chief and Olympics plans were fully formed — indicated the state might need some combination of the three locations to park empty trains during the day.

For years, the state has wanted to expand South Station, which has maxed out at 13 tracks. The project would add seven tracks to reduce delays and allow for new commuter rail and high-speed train service.

Mayor Walsh has supported the effort for a bigger South Station and even went down to Washington last fall with Pollack to meet with US Postal Service officials. In order for the state to move ahead, the Postal Service needs to give up its main Boston facility, which abuts South Station. The state has proposed a land swap with the Postal Service and agreed to build a new facility in South Boston. So far the two sides have not come to an agreement.

This is not the first time the state has eyed Widett Circle for a rail yard. In 2001, the MBTA considered taking the area by eminent domain, but then-Mayor Tom Menino halted those plans because it would displace two dozen meat and seafood food processors.

Pollack acknowledged that an earlier version of the environmental report included eminent domain as an option for Widett. Pollack said that is not a preferred technique, but she would not rule it out.

“I know it was under consideration at the draft stage,’’ Pollack said. “I don’t want to talk about what we’re going to have in the final until we get to the final.’’

During the Olympics discussion, Walsh had promised the businesses in Widett Circle that the city would not take their land by eminent domain — and that is something he stands by today in developing plans for the area.

“I would be very concerned about using eminent domain powers, particularly in the city of Boston for the layover of tracks,’’ Walsh said.

The most prominent landowner in Widett Circle is the New Boston Food Market, a cooperative consisting of more than 20 businesses employing about 900 people. Michael Vaughan, a real estate consultant to the cooperative, said the market is exploring a move but frowns on others making plans for its property before it has found a new home.

“We’re sick of things being done to us,’’ Vaughan said. “We prefer things done with us.’’

The reality is that if the state wants to grow South Station it will need more layover tracks somewhere in Boston.

What Walsh needs is time to make his case, and time is on his side. The final environmental report must go through a public comment period, followed by other reviews. In other words, it will take several years before South Station expansion really gets serious.

Pollack told me that if the city’s future plans for Widett come into sharper focus, the state can revisit whether it needs a layover facility there. But in the next few months, the state has to outline how it wants to expand South Station.

“There will be time to make changes,’’ Pollack said.

Let’s hope so.

Olympic dreams fade fast in this town, but the future of Widett Circle should be bigger than a parking lot for commuter trains.

Shirley Leung is a Globe columnist. She can be reached at shirley.leung@globe.com. Follow her on Twitter @leung.