The large roundhouse building in the former U.S. Steel plant in McKeesport reminds visitors of the past and represents new opportunity.

Thus, local leaders want to use the building, a semicircular brick structure once used to switch and service locomotives at the mill, to capitalize on what they say is a unique combination of local heritage and a new heyday for the site. The 150 acres of former mill site land in McKeesport is about a third developed.

At its peak in the 1940s, the McKeesport National Plant steel mill employed 8,500 workers. Now, about 1,500 people work at seven small businesses on the site. The largest employer is EchoStar Inc., a satellite dish provider, which employs 1,200 at its McKeesport facility.

With the addition of several businesses to the site in the past few years, the long-vacant roundhouse is a promise for the future, in the eyes of members of the Regional Industrial Development Corp. of Southwestern Pennsylvania, which owns and is developing the old mill site. The roundhouse sits on the river side of the site, across from the 1905 Building, a historical building now occupied by Maglev Inc.

"This is a place we want to keep as a historical reminder, to complement the industry that's going on here. The structure itself is like a fortress," McKeesport Mayor Jim Brewster said.

"I liken this to what they did down at Station Square. RIDC has a vision for this building, and we're happy about that."

The vision is to capitalize on the historic nature of the building and make it into a destination point, such as a restaurant, if possible, said Robert Seymour, RIDC project manager.

The brick roundhouse remains sturdy, with just a few holes in its roof. Inside, a handful of vintage Port Authority buses are collecting dust, stored there by a local club which owns them. The only sign of its previous life are the 4-foot-deep trenches cut into the floor that were used by mechanics when working on the trains.

But RIDC officials say the 20,000-square-foot structure has the right location and the "bones" to be turned into a new restaurant, or into a mixed-use facility with a dining establishment and some boutiques.

Or the place could be used for manufacturing.

"If someone came in and had the wherewithal to rehabilitate this place, we'd be willing to talk to them," RIDC site Manager Rebecca Spencer said. "Our mission is to work with industry to provide a place for business growth and employees."

The group has cleaned up the riverfront behind the building to make it more attractive to developers, Brewster said.

"I tell people that this is the best- kept secret in town," he said.

"Obviously, we're interested in taking advantage of this building. At this point, it's whatever we can get. Shops would be nice, but there are other opportunities."