HARTFORD — State planners are inviting the public to offer suggestions on what should be done with historic Union Station after a new train station is built as part of the I-84 viaduct replacement.

The Department of Transportation is holding forums on Thursday in Hartford and April 25 in East Hartford to learn what people think.

“We’ll have brief presentations, but mostly what we want to do is listen to the public and hear ideas,” said Richard Armstrong, the DOT’s project manager.

The state intends to rebuild a 2-mile stretch of elevated I-84 through the city. Its plan is to construct a new one at ground level or slightly below, and so far public attention has focused mostly on whether the new section of highway could be a tunnel.

But a central part of the plan involves relocating a mile or so of railroad tracks, a change that would essentially strand Union Station because Amtrak’s line would go about two blocks to the west.

The DOT envisions a new station for trains and buses, possibly between Garden Street and Asylum Avenue. Planners say it would be a transit hub serving taxis, pedestrians and cyclists.

That leaves the future of Union Station in limbo, though, and some residents are suggesting it be retained as bus station for Greyhound, Peter Pan and possibly CT Transit services. The DOT has also heard recommendations to make it a museum.

“It is also listed on the National Register of Historic Places, and will remain a protected landmark,” the DOT said in its I-84 project newsletter. “However, it’s poised for change. Could it become a reinvigorated commercial center, a hub for bus operations, or another idea that has yet to emerge?”

The station was built in 1889 and reconstructed 25 years later because of a major fire. It houses the Greater Hartford Transit District offices, and handles passengers for about a dozen Amtrak trains a day as well as long-haul bus riders.

The frequency of trains is scheduled to rise sharply next winter when the Hartford Line commuter operation begins, and Union Station will be its Hartford stop for at least a few years. The state last year spent about $3 million to improve Union Station’s handicapped accessibility and security while installing a 260-foot-long, elevated platform to speed loading and unloading of passengers.

Even under optimistic projections, construction of the I-84 project won’t begin for several years.

The DOT is also looking at redesigning the I-84 and I-91 interchange, and seeks the public’s ideas about that, too. The Thursday and April 25 sessions will include time for discussing Union Station as well as the interchange.

The schedule both days includes an open house from 4 to 8 p.m., with a presentation at 5:30 p.m. and separate workshops at 6:15 p.m. to explore the I-91 interchange and Union Station issues. The Thursday session will be at the Hartford Public Library at 500 Main St.; the April 25 session will be at the Raymond Library, 840 Main St., East Hartford.