Area congressmen gathered this week to congratulate themselves on their wisdom (in an election year) of proposing a study of Metro subway extensions to almost everywhere. But the U.S. Department of Transportation sounded a cautionary note.

Lillian C. Liburdi, deputy administrator of the department's Urban Mass Transportation Administration (UMTA), told the congressman that DOT does not oppose the proposed study as a concept, but that it should not be assumed that a subway is the best method of meeting transit needs along the proposed routes.

"Any comprehensive study . . . must include an analysis of alternative methods," Liburdi said. She also said that UMTA thinks future extensions for Metro should be considered equally with transit projects elsewhere in the country.

Her comments, however, did little to dampen the enthusiasm of Rep. Herbert E. Harris II (D-Va.), Joseph L. Fisher (D-Va.), Michael Barnes (D-Md.) and Gladys Spellman (D-Md.), who had met at the Capitol on Thursday to praise the proposed study, which Harris has offered as legislation. D.C. Del. Walter Fauntroy (D) is a cosponsor of the bill and even Re. Marjorie S. Holt (R-Md.), not always Metro's most enthusiastic supporter, provided a statement supporting a study.

Harris and Fisher thought it would be nice if Metro were extended to Dulles International Airport, Burke, and even the intersection of Interstate 66 and U.S. 50.

The Dulles line is seriously regarded by many people as Metro's most logical extension, and Rep. Stewart B. McKinney (R-Conn.) said he will introduce legislation authorizing federal funds for such an extension.

Barnes is excited about the prospect of pushing the Red Line all the way out Montgomery County to Germantown. Spellman dredged up a proposal not heard seriously around here for almost a decade -- an extension of the Greenbelt line to Laurel where, someday, it could connect with the Baltimore subway, now under construction. Maryland proposals include extensions to Bowie on the east add to the Prince George's-Charles County line on the south.