Most Northern Virginia legislators agreed today to support Gov. John N. Dalton's 4-cent-a-gallon gasoline sales tax increase -- provided the measure earmarks sufficient revenues to pay for Metrorail construction.

In contrast to the sharp division that surfaced two weeks ago in the 27-member delegation, the region's law-makers moved quickly today to endorse the governors's statewide tax bill and to offer several local taxing options as back-up legislation should the Dalton proposal falter.

The Northern Virginians backing the Dalton bill, which is intended to raise $130 million annually for highway and Metro construction, stressed that their support will evaporate if the pledge of Metro money is dropped from it.

"Not only would we not support the bill, I think we would oppose." warned Del. Warren E. Barry (R-Fairfax).

To which State Sen. Adelard L. Brault (D-Fairfax), the delegation's chairman, added: "You can count on my help."

The Dalton bill, sponsored by Del. Vincent R. Callahan (R-Fairfax), has met with much hostility. Some legislators say they are skeptical of the state highway department's claims of declining revenues, while others are opposed to raising the gasoline tax (from 9 cents to 13 cents) and using some of the funds for mass transit in the Washington suburbs.

Northern Virginia legislators have been anxious for increased state aid to their beleaguered transit system and need to find a "stable and reliable" source of operating revenues if Metro is to tap a share of a $1.7 billion federal transit aid package.

Only freshman Del. John S. Buckley (R-Fairfax) expressed any reservations about the Dalton gasoline tax measure at today's delegation meeting and he ultimately abstained when a formal vote was taken. Four other members of the delegation were not present when the 22-0-1 vote was taken.

"I'm not prepared at this point to go on record saying I'm in favor of the governor's gasoline tax," said Buckley, one of te region's more conservative legislators. "I'm not entirely convinced that every time there's a need for more services, it means there's a need to raise taxes."

He suggested, instead, that funds for other services could be trimmed.

The other area legislators said the issue of Metro funding was urgent.

"We've reached a point where we have to make some decisions," said Brault, who reminded the delegation that it must leave the Assembly this session with concrete proposals to deal with the Metro funding crisis.

Brault recommended a course of action he said had worked out by delegation leaders, including those who serve on the Northern Virginia Transportation Commission. They agreed to back Dalton's 4-cent-a-gallon tax and to attempt to amend the measure by adding specific language to safeguard revenues for Metro.

If the Metro revenues remain in the gasoline tax measure, Brault said, Northern Virginia localities would be relieved of a substantial portion of the subway's construction costs.The communities then would have more funds available to pay the transit system's mounting operating costs, he said.

Reporting on a recent meeting with Transportation Secretary Neil Goldschmidt, Brault said that the federal requirement of securing a stable and reliable source for the operating costs could be met by dedicating a portion of existing local government revenues for that purpose.

Several other members of the delegation announced plans to introduce additional tax measures on behalf of Metro, including a 1-cent regional sales tax. It was agreed, through to delay taking a delegation position on these controversial alternatives until there is a clearer idea of how Dalton's tax proposal will fare.

In another display of unity, area lawmakers condemned as 'vitrolic and irresponsible" a story in The Washington Post on Monday on one of their own, Sen. Charles L. Waddell (D-Loudoun).

"It was an outrageous article, simply outrageous," complained Brault after the delegation unanimously adopted a resolution accusing the newspaper of doing "a great injustice" to Waddell, his family and his constituents.

Earlier in the day the article -- which dealt with Waddell's effort to make a Republican a judge -- provoked an outburst on the Senate floor from majority leader Hunter B. Andrews (D-Hampton).

While Waddell wiped tears from his eyes, Andrews complained that the article had "demeaned" the entire Senate by including what he called "offensive" remarks about Waddell's profession and the attire of his wife. He then asked that all the senators stand and applaud the Loudoun legislator as a show of support. They did.