A federal judge told the Virginia Highway Department yesterday it can move equipment into place for construction of Interstate Rte. 66 inside the Capital Beltway but may not start construction until he decides a suit that seeks to block the project.

Construction of the long-stalled project was to have begun Monday.

U.S. District Judge Oren R. Lewis scheduled trial of the suit, filed by the D.C. Federation of Civic Associations and three other groups, for July 26.

Former U.S. Secretary of Transportation William T. Coleman ruled last year that the highway could be built despite protests of Northern Virginians who fought 1-66 on environmental grounds.

The civic associations claim that Coleman's ruling is invalid and alleges that it was based not on environmental impact statements but on a deal giving approval of I-66 in return for agreement by Virginia Gov. Mills E. Godwin to make funds available for Northern Virginia Metro construction.

At one point, Lewis said, "you're not going to delay this road forever. There comes a time the good citizens of Northern Virginia and the good citizens of the District - I'll put them all together - have a right to know the finality of (I-66)."

In another I-66 development, the Fauquier County Board of Supervisors voted Thursday to seek elimination of an interchange planned on the portion of the highway that is outside the Beltway. The interchange would be just west of Thoroughfare Gap, near the Prince William County line.

The final decision on the interchange, one of six planned in the county, will be made by the state highway department. Highway Commissioner John E. Harwood said yesterday that it "is a rather late date for considering removing the interchange" but that if the board wanted it removed "we would have a public hearing and consider it."

Harwood said his department was in the final stage of processing an advertisement for construction bids including the interchange, which he estimated would cost about $500,000. He said that the County Board had twice before endorsed the interchange and that "I'm not at all convinced that we should eliminate it."

Foes of the interchange have argued that it would open the eastern edge of the developers and the county newspaper editorialized strongly against it, calling it "a most questionable million dollar windfall" for a few large landowners with plans for development.

John T. Hazel, a prominent Fairfax zoning lawyer whose family owns about 2.500 acres near the interchange, said "Hazel family resents the hell out of" that view. He said his family had bought that land 30 years ago and that he had been working on the farm "before I was even in law school . . . My children would disown me" if it were sold off for development.

Hazel said he doubted that the interchange would have any measurable impact on land use or property value since there would be other interchanges within five miles both to the east and west.