The city of Alexandria, the Southern Railway and the United Parcel Service have reached an agreement that preserves a Metro station site for a possible rail line, Alexandria Mayor Frank Mann told the Metro Board last week.

The agreement was worked out after UPS expressed interest in buying part of the planned Metro site from its current owner, the Southern Railway.

The proposed Metro line would run above ground from Alexandria's planned King Street Station west to a station near South Van Dorn Street and Eisenhower Avenue, then continue west of Springfield-Franconia in Fairfax County.

However, Metro does not have an option - or the money to secure an option - on the Southern Railway property for the Van Dorn Street station and a major commuter parking facility to accompany it.

The proposed line from King Street to Springfield-Franconia is one of several Metro segments that is being studied by a regional task force to determine if there are enough potential riders to justify the high cost of building a rapid rail system.

That study is scheduled for completion sometime in October. Then, if a case can be made for the Springfield line or a section of it as far as Van Dorn, Metro would apply for federal and local funding to acquire the property.

In the meantime, however, UPS has approached Southern Railway about building a distribution center on Metro's proposed parking lot. The UPS proposal was routinely approved by the Alexandria Planning Commission then forwarded to the City Council.

"But we can't keep a private land owner from developing his land. Mann explained to the Metro Board. Although Metro has the power of eminent domain - the unquestioned right to acquire property for the government - property with a new warehouse on it would be much more expensive than unimproved land.

The compromise. Mann said, provides for UPS to move the site of its building and employee parking lot. Metro would have free air-rights to build on top of the employee lot.

Futhermore, Southern Railway would preserve for Metro for six months 5.5 acres of land to be used for parking. If it is decided to extend the Metro Line to the Van Dorn Station, Southern would give Metro another six months to purchase the land.

Mann said that under the compromise, Metro would only have to redesign its parking lot, not its station. The redesign would require planning commission and City Council approval, however, and the compromise will cost Metro more money in construction of the Van Dorn Station.

Metro's assistant general manager for design and construction, Roy T. Dodge, said last week he had not had time to make preliminary estimates on what the compromise would cost if Metro builds the Van Dorn Street station.