Transportation Secretary Brock Adams and Washington area officials reached a compromise yesterday that appears to guarantee both continued federal support for the Metro subway and a train line to Wheaton.

The agreement was hammered out in Adams' office in a difficult two-hour meeting, after which representatives of both sides emerged looking a little but unhappy.

"I think we have a resolution," Adams said. As Adams and other outlined it, the planned subway line from Silver Spring through Forest Glen and Wheaton to a terminal in Glenmont will undergo an "engineering analysis" to determine means of cutting costs.

The line is presently planned as a $275 million to $300 million deep rock tunnel that, mile for mile, would be most expensive suburban segment in Metro's planned 100-mile system.

The engineering analysis, Adams said, would be both "horizontal and vertical." Translated, that means that the specific route the track would follow will be studied as well as whether the train should be run in a deep tunnel, a shallow tunnel, on the surface, or on an elevated structure. The latter three choices, Adams said, "all involve enormous savings."

All of these possibilities are called "heavy rail" in transportation terminology. "At this point," Adams said, "we still feel that this (line) looks like heavy rail."

That means that a full series of alternatives for that transportation corridor - including bus lanes or a trolley down the middle of heavily traveled Georgia Avenue - will not be studied.

Adams also said that his staff and area representatives were "trying to work out the interim financing" for Metro. A $12 million bill - interest on Metro construction bonds - comes due July 1. The bonds are federally guaranteed and Metro officials are trying to get the federal government to pick up the tab.

Various legislative and adminstrative ways of creating the money by the deadline are still under discussion, officials said.

Before yesterday's meeting, Adams had linked agreement on a restudy of the Wheaton line to future administration support for Metro bond financing . That obstacle has thus been cleared away.

The area negotiating team included Francis White, a Prince George's County councilman and chairman of the Metro board, Sterling Tucker, chairman of the D.C. Council and member of the Metro board, Harold Miller, Falls Church mayor and chairman of the Council of Governments board, and John Freeland, a member of the Rockville City Council and chairman of the regional Transportation Planning Board. Staff members also attended.

At one point, Metro General Manager Theodore Lutz, who had to catch a plane, fled from the meeting room exclaiming, "They're not gonna' give." Others who attended the meeting said that after about 90 minutes of discussion somebody said, "Isn't there someway to work this out" and that the room was silent for "what seemed like 30 seconds."

Then the compromise began to unfold.

In two recent letters to area officials, Adams had said that he wanted the Wheaton line added to "alternatives analysis." Several suburban and one inner-city line are currently under a restudy that considers the use of trolley or bus, instead of train, as well as route alignment and construction questions. The Wheaton line had previously been eliminated, with Ford administration approval, from that study.

The "engineering analysis" on the Wheaton line will be folded in to the "alternatives analysis" in October, officials said yesterday, when the tough decisions must be made about which Metro lines will be completed.

Engineering staffs from the Urban Mass Transportation Administration, one of Adam's responsibilities, will work with the Metro engineers on the study.

Metro board chairman White, who spoke for the others there, said he thought the compromise would be acceptable. "I'll know more," he said, "after I hear from Mr. Gleason."

Montgomery County Executive James P. Gleason adamantly opposed "alternatives analysis" for the Wheaton line on the grounds it would take too much time and that some of Adams' staffers had already decided against it.

Adams called Gleason last night and explained the compromise to him.

"I told him that was encouraging news," Gleason said. Earlier he had told a reporter, "It sounds to me like they're trying to find a way to cut costs - and that's fine with me. For one thing, we can certainly do without these grandiose underground stations out here."