The Evans Co.'s opening act in Washington--transforming the historic Old Post Office building into a showcase of restaurants, shops and offices--played to rave reviews and SRO crowds this week.

The new project, called the Pavilion, promises to be one of the major attractions of the Pennsylvania Avenue Redevelopment Plan.

Overlooked in the hoopla over the restoration of the Old Post Office, however, is the potential impact of this project on further development of Washington's downtown. The Pavilion can't be duplicated but the concept of retrofitting old buildings for a variety of commercial uses can be.

Until now, there has been little of this kind of redevelopment in that part of the city. The new Sears International Trade headquarters, also on Pennsylvania Avenue, is a rare example.

Unlike most developers who have recently been attracted to the central business district and adjacent areas, the Evans Co. sees greater opportunities in developing more retail space.

"We need more than office buildings," says the firm's president, Charles C.G. Evans. Development of office buildings, he adds, has a "momentum that's only one part of our life. What the Pavilion offers is an opportunity to enjoy people instead of paper."

As an encore, Evans plans to redevelop similar mixed-use projects, featuring retail centers, elsewhere in the central business district and beyond. There are, for example, two buildings on nearby Pennsylvania Avenue that lend themselves to the same type of mixed-use redevelopment, he said.

Evans is understandably reluctant to discuss details of negotiations, but it's apparent that he intends to duplicate the concept of retrofitting old buildings as retail centers. This approach, new to Washington, could significantly influence development trends, retail patterns and shopping habits in the central business district.

Contrary to a popular belief held by many in Washington's established retail community, Evans doesn't believe the area is "overstored." In the District, at least, shopping areas are "under-stored," he contends.

There is, he says, a need for smaller, specialty stores that "are not competitive but supportive of large anchor stores" in the central business district. "Downtown Washington is under-stored in a way that offers an opportunity to provide more in the marketplace."

With 50 small shops and restaurants, the Pavilion doesn't fill the void left in downtown Washington by the exodus of retailers and the drawing power of suburban shopping malls, Evans points out. Nor will the 100 specialty shops and restaurants at National Place, which is being built across the street, he adds.

"There is still plenty of room for a mix of ideas and new merchandising concepts, not just retail," Evans says. "What's happening out there is a whole mixture of buying habits and all of our lifestyles are changing. There is no longer a syndrome of going to a regional shopping mall on Friday night. Patterns have changed, so there are new opportunities."

That doesn't quite square with the findings in a recent Post survey in which a majority of those polled said they prefer shopping in suburban malls.

Nonetheless, Evans is convinced that several Pavilion-like projects will produce not only a living downtown but the re-emergence of a strong retail base in the city.

And that can be accomplished, he maintains, without building massive structures to house urban specialty retail centers. "Once you get over 60,000 to 80,000 square feet, you begin to get duplication and that begins to diminish what you're trying to do."

Size, nonetheless, is not a drawback to Evans' plans to transfer his redevelopment concept to other buildings. Union Station, for example, could become pivotal in those plans.

"I believe there is an opportunity at Union Station," Evans candidly acknowledges. "We're looking at it very closely, so that we will be ready when they ask for proposals."

The once-grand train terminal at First Street and Massachusetts Avenue NE stands idle and crumbling, a colossal and mute testimony to nearly 20 years of congressional and bureaucratic bungling.

The Department of Transportation has pledged $70 million to be used over the next five years to restore the station as a train terminal. To take advantage of the station's economic potential, DOT also proposes to have it developed as a commercial center.

Listening to Evans, it doesn't take long to conclude that he has already developed a concept for Union Station and very likely is a step ahead of other would-be developers.

"I think Union Station needs to be a mixed-use project but it needs to be a major destination for people" to make it a viable commercial center, Evans asserted. "We would do something that's never been done before."