CLEVELAND, Ohio -- A long-held dream to build an intermodal transportation center that would be a hub for local buses and rapid transit, Amtrak trains and Greyhound service is inching closer to reality.

The Greater Cleveland Regional Transit Authority and the city of Cleveland are preparing to strike an agreement for a joint study of whether rail and bus operations could be united under one roof in a transit center near Lake Erie.

RTA's Planning and Development Committee will take up the issue at 9 a.m. Tuesday at the agency's headquarters at 1240 West Sixth Street in Cleveland.

Also on the agenda: An update on the redevelopment of Public Square, including information on interim bus stops during the 18-month construction project; and discussion of a study on RTA's outdated rail stations at East 34th and East 79th streets.

There's been talk for years about an intermodal station but factors such as a decline in the now reviving Flats entertainment district put plans on hold.

Valarie McCall, who heads RTA's important planning and development committee, said recently that discussions on a transit hub gained new momentum because of Greyhound's work with the city of Cleveland to vacate its historic Art Deco terminal in downtown Cleveland.

Playhouse Square leaders are thought to be closely involved with plans to repurpose the Greyhound terminal on Chester Avenue - part of a drive to build up retail in neighborhoods flanking the theater district and Cleveland State University that have a growing residential population.

RTA General Manager Joe Calabrese said in November that he helped broker talks between Greyhound and developers interested in the iconic 1948 bus station. Greyhound confirmed that it's investigating a new, modernized location for its Cleveland operations.

Meanwhile, Amtrak has to make improvements to its lakefront station to comply with Americans with Disability Act requirements. Along with a deteriorated station, Amtrak customers have had to deal with chronic delays, a problem that's led Northern Ohio's metropolitan planning organization to see what can be done to smooth service.

With key pieces of Greater Cleveland transit in flux, planners say now could be the right time for creating an intermodal center that would route everything from rail to taxi cab service through a central hub.

Before joining RTA, Calabrese oversaw the development of the Walsh Regional Transportation Center in Syracuse, New York. Boardings on all transportation modes grew 20 percent after the center opened in 1999, he has said.

The rail advocacy group All Aboard Ohio estimates that 1 million people a year would use a multimodal center in Cleveland if RTA, Greyhound, Amtrak and other lines that feed into downtown, such as Laketran, Akron Metro RTA and Megabus, as well as taxi operations, were coordinated out of one location.

"That's more than what occurs at the Akron-Canton Regional Airport. That's enough to support spin-off retail, restaurants, rental car counters, car sharing and bike sharing services at the center. This would be like having an airport in downtown Cleveland," All Aboard Ohio Executive Director Ken Prendergast said in an on-line posting.

All Aboard Ohio proposes putting a transit hub just north of the convention center and linking it to renovation of the Amtrak station along the lakefront tracks between West 3rd and East 9th streets.

The city of Cleveland had that general location in mind in 2010 when it announced plans for a multimodal center north of the east edge of Mall C, possibly extending over railroad tracks to just south of the Shoreway, with walkways to the mall and North Coast Harbor.

Then-city planning director Bob Brown said at the time that the station, which would also include a parking deck and bicycle connectors, could be one of the most complete multimodal centers in the United States. Aside from hosting transit, Brown said, it would help link the new medical mart, convention center and Flats east bank redevelopment.

But plans stalled, in part over the cost, estimated at $50 million, much of which would have to come from state and federal sources.

More recently, Prendergast said last week, there's been "some pretty underwhelming discussion" about locating a hub at the far east end of the Cleveland Muni Lot on Marginal Road.

"As far as I'm concerned, that's Siberia," he said. "If you're a low-income Cleveland resident and trying to get to the Greyhound station, how do you get there?"

Prendergast also noted that one of Cleveland's Amtrak lines doesn't run next to the Muni Lot.

While the Lakeshore Limited line from New York City and Boston is close by, the Capitol Limited from Washington, D.C., doesn't merge with the Lakeshore Limited tracks until 1,000 feet west of the parking lot.