The Metro board unanimously recommended yesterday the construction on a "high-priority basis" of a lower-cost subway line from Silver Spring to Glenmont and thus tossed the controversy back to the federal government.

In a carefully engineered resolution that is clearly an attempt to keep Metro's regional coalition intact, the board also proposed as a high priority that funds be found to complete subway segments between downtown Washington and Anacostia and between L'Enfant Plaza and the Pentagon.

The recommended method for constructing the Glenmont Line would mean that the three stations on it - at Forest Glen. Wheaton and Glenmont - would be smaller and lack the vaulted ceilings of the underground stations already completed. This first major departure from Metro's grand design would make the cost of the 4.6-mile Glenmont Line about $347 million - or $25 million less than present plans specify.

It remains to be seen, for two reasons, whether board's action will be enough to solve a complex problem that threatens the financial underpinnings for 60 miles of Metro's planned 100-mile system and has stopped all new Metro construction.

There is some question whether the board's resolution yesterday will be interpreted as meeting the conditions for federal consideration of the line that were laid down two weeks ago by Richard S. Page. Page, administrator of the Urban Mass Transporation Administration, is the key adviser to Transporation Secretary Brook Adams, who must make the final decision on whether to approve 30 percent federal funding for the project.

There is also the question of whether federal statements on the matter will be quick enough and supportive enough to persuade the state of Maryland to release $328 million in Metro construction funds.

Maryland Transportation Secretary Hermann Intemanns signature is needed on a federal regional contract before that money can be spent. For more than two months, Intemann has declined to sign the contract at the request of Montgomery County Executive James P. Gleason. Gleason wants a federal guarantee to build the Glenmont line though the densely populated Georgia Avenue corridor before other Metro construction can proceed.

The $328 million being withheld is programmed for construction in Virginia and the District as well as Maryland. While most regional politicians have agreed with Gleason's goals several have questioned his tactics and some - notably Alexandria City Council members have been infuriated by them. Construction of Alexandria's King Street station on the extension from National Airport to Huntington is among the projects that have been delayed. Most of the rest of the money is for extending the Dupont Circle line to Shady Grove.

Gleason had no comment yesterday on what his next move will be. The Montgomery County Council has already recommended that the funds be released. Intemann said through a spokesman that he wants to see what the federal reaction is before he decides whether to sign the contract.

Page met with area officials two weeks ago and told them he would consider a request for federal funding of the Glenmont line if four conditions were met:

1. The Metro board recommends constructions of the line.

2. Local governments are willing to transfer enough money from their federal interstate highway entitlements to pay for the federal share (80 per cent) of the Glenmont line.

3. The local share (20 per cent) of the construction money is assured.

4. The Glenmont Line is declared a priority.

Page used the term "first priority" in discussing the conditions with a reporter. Metro Board Chairman Francis White who attended the meeting, said yesterday that "my understanding was that the Glenmont line) was to be given a priority - not one with an adjective connected to it."

The board resolution yesterday did not guarantee interstate highway entitlements of the local share although it directed Metro General Manager Theodore Lutz to develop a [WORD ILLEGIBLE] plan and funding arrangement for the entire high-priority package. Glenmont line, Anacostia spur and L'Enfant Plaza-Pentagon connection.

Completion of those three pieces would give something to everybody. Virginia would get a quick rail connection across the Potomac River to the Southwest; the District would get a line under 7th Street NW from about G Street south through the L'Enfant Plaza station, then east through the Navy Yard and across the Anacostia River into Far Southeast; Maryland would get the Glenmont Line.

Construction has been completed on major parts of all of those lines, but funds are not available or in the present 60-mile agreement to complete any of them.

The segments total about 11 miles and, if completed, would carry Metro to 71 miles. None of those segments is part of the study a regional task force is completing to decide the future of four Metro lines.

Gleason, Lutz, White, D.C. Transportation Director Douglas Schneider and Montgomery County Board Member Cleatus E. Barnett, among others, pulled the proposal together. Phone calls were made by at least one member of that group to Alexandria Mayor Frank Mann and by another to Arlington County Board Member Joseph Fairfax County Board Member Joseph Alexander was also aware of the proposal and voted for it.

"If we don't hang together on this, they're going to rip us apart," Alexander said later.

There is a belief among many regional officials that some federal offcials opposed to the Glenmont Line have hoped to so divide the Metro partners that they themselves would kill Glenmont and relieve the federal government of a tough decision.

Despite the phone call to Mayor Mann, however, Alexandria may not be in the fold. Alexandria City Council Member Robert Calhoun said yesterday that "Montgomery County has broken faith with us (by withholding the construction funds) and they can whistle before they're going to get any money from us." The Alexandria Council, he said, discussed the situation in executive session Tuesday night and decided to "just let it ride."

Page, the UMTA administrator, said yesterday afternoon that he had read the board resolution but wanted further briefings and meetings before deciding what action, if any, to take.

UMTA staff members are also studying the cost figures on the Glenmont line: one study they have commissioned indicates that Metro's consultants overestimated on one possible construction alternative, according to sources.

"I don't have a firm deadline for a decision one way or the other," Page said." . . . We're still reserving the option of not reaching a decision on the Glenmont line" until the regional task force completes its work on the four other lines and a long-term financial plan is in place for Metro's construction and operating costs.