Its roof may leak and its facade may be crumbling, but its future is no longer in doubt. Alexandria's Union Station, the 77-year-old Colonial Revival style passenger train station on the fringes of Old Town, soon will undergo major exterior renovation--a decision that's been met with delight and relief from those who use the station as well as those who just like to sit nearby and watch the trains roll past.

And if the city has its way, renovation will not end at a facelift.

Under an agreement signed in late March between Amtrak and the Richmond, Fredericksburg and Potomac Railroad, which owns the station, Amtrak will spend $200,000 and the RF&P $50,000 to make emergency repairs that will keep the station open.

In addition, a $95 million development plan submitted by an Alexandria group that calls for construction of a hotel and convention center spanning the railroad tracks just south of the station must include renovation of the station's interior as well, say city officials.

The decision to shore up the station's exterior comes after two years of haggling between Amtrak, RF&P, city officials and nearby residents.

Residents have feared that RF&P might want to close Union Station and use the site for more profitable development. Property values in the area have escalated in recent years with construction of the King Street Metro station, which faces Union Station across the tracks and is scheduled to open in late 1983.

"Past relations with RF&P have been checkered," said City Councilman Donald Casey, an attorney who lives four blocks from the station. "We've traded some harsh words, but I think it finally penetrated Richmond (RF&P headquarters) how serious we are about Union Station as a landmark."

Henry Williams, who's been Union Station's baggage handler for 40 years, called the renovation plans "a dream come true." "It hurt my heart when I heard they might be thinking of tearing it down," he said.

Saving Union Station has been part of the city's plan for the upper King Street area since the plan was developed in 1978, say city officials. The plan calls for a mix of residences, stores and offices around the Metro stop, tied together by promenades, pedestrian bridges and small parks and served by underground parking and Metro. Within the plan, "saving Union Station has always been one of the items we considered nonnegotiable," said City Manager Douglas Harman.

RF&P never intended to tear down the station, said RF&P Vice President Richard L. Beadles, but people became increasingly concerned about just what the railroad did want to do with it as the physical condition of the station worsened.

Delays in repairs to the station were caused by a dispute between Amtrak and RF&P over who was responsible for major repair work, according to Larry K. Grossman, senior planner with Alexandria's Department of Planning and Community Development. "The arguing would have gone on indefinitely if the station hadn't been in such sorry shape," said Grossman.

Rotting columns barely supporting the station's west-side passenger platform canopy, rotting crossbeams in outside stairway canopies, extensive termite damage to timbers holding up a porch on the station's northwest corner and a leaking roof forced Amtrak's hand, said Alan F. Edelston, Amtrak's director of state and local services.

"The station was really becoming a safety hazard," Edelston said. "We couldn't have used it for much more than a year if repairs weren't made."

However, Grossman said there were other reasons for saving the railroad. "RF&P is probably the largest landowner in Alexandria, and right now they're wearing their developer hats," he said. "They know the city's position on saving the station, they know they need the city's cooperation on development projects--so I think the renovation was a gesture of good will."

Edelston said Amtrak also wanted to keep open Union Station, which ranks as one of their busiest 50 out of nearly 500 stations. As the destination or jumping-off place for more than 70,000 passengers last year, the station is prized by those who use it for its convenience and accessibility.

Work on the station, which is expected to begin very soon, says Edelston, will include restoration of all station canopies except the one facing the George Washington Masonic Memorial, which will be removed. The roofs on the station and on the baggage and storage building will be repaired, all brick and stonework repointed, all window frames repaired or replaced, exterior lighting rewired, seven new lamps added in front of the station and all woodwork scraped and painted, he said. A tunnel connecting the east and west sides of the passenger platform, now closed for safety reasons, will be reopened so passengers will not have to cross the tracks to catch northbound trains.

"From what we've seen of the plan drawn up by Amtrak architects , we have absolutely no problem with it," said Calder C. Loth, senior architectural historian with the Virginia Landmarks Commission.

The station, which Loth describes as "one of the finest examples of Colonial Revival architecture in the state," bears no historical designation. It sits outside the bounds of the Old Town historic district and is not covered by the city's building-protection ordinance since that applies only to buildings over 100 years old. The station also has not yet made it onto the National Register of Historic Places, though a nomination is pending.

Historical designations afford buildings varying degrees of protection from alteration or demolition, and in some cases provide economic incentives to restoration.

Nearby neighborhood groups seem satisfied with the restoration plan.

"I think there is a reasonable assumption that the station will be saved now," said Kerry St. Clair, president of the Rosemont Citizen's Association. "Its continued use as a passenger facility is what we've wanted all along."

Grossman said he sees the station's role expanding to handle commuter traffic, linking farther-out Virginia areas to Metro and downtown Washington.

Although renovation of the train station already has gained approval, debate still is brewing over development plans for an adjacent tract just yards to the south, including land on which the station parking lot now sits. Those plans, submitted by Station Square Associates, a consortium of Alexandria-based businesses, calls for construction of a plaza spanning both the RF&P and Metrorail tracks and holding four highrises: a 300-room luxury hotel, a convention center and two office buildings.

"We all recognize the need to develop upper King Street," said Councilman Casey. "And I like the idea of a hotel up there. We just don't want to kill any neighborhoods in the process. People who live near me are not happy about intensive use on the site and what that will do to traffic and parking in the neighborhood, and I agree with them."

Plans for the project have not yet gone to the city for approval. That will come after the Washington Metropolitan Area Transit Authority (WMATA), which owns the land on the east side of the tracks, and RF&P, which owns the land on the west side, reach agreement, according to Dick Miller, development manager of WMATA. The two jointly own the air rights over the tracks.

Two stumbling blocks to approval could be needed zoning changes and disposition of the Vepco transmission lines that now stand in the path of the development site.

Both the city and neighborhood groups want the lines put underground, "but that will cost between $8 million and $13 million," said Casey. He said the city would not fund any portion of that and would "sit on any plan" that calls for rerouting the lines above ground.

The land also must be rezoned for the project since land on the west side of the tracks now is zoned for residential rather than commercial use.

"We would definitely have to be convinced that there would be strong advantages to having development" on the west side, said St. Clair. "And what if the land is rezoned for commercial use and then financing for the development project falls through, leaving the land vulnerable to unknown development at a later date?"

He said residents also "don't want to see the station overshadowed," by the design of the hotel/office/convention center buildings.

Architects for the project--from the Alexandria firm of Vosbeck, Vosbeck, Kendrick and Redinger--have indicated they may seek permission to build higher than the 77-foot maximum height limit on buildings in this area that local residents fought for and secured in 1978.

No matter what form the final plan takes, said city planner Grossman, it will mean money for renovating Union Station's interior. "Any plan we ultimately approve will have to accommodate creative adaptive reuse of the station," he said.

But precisely what kind of "adaptive reuse" remains to be worked out. Donley F. Hunt, president of Investment Properties Inc., one of the businesses in the development consortium, said they have considering putting a restaurant in the station, but Amtrak's Edelston said he doubts there would be sufficient space for that.

Despite the potential snags, all parties seem to agree that some plan eventually can be worked out.

"We're not opposed to development," said St. Clair. "You have to be realistic. Mixed use of the area will be good for the city. We just want it to have the least adverse impact possible."