CALL IT A "deal" or politics at its bring-home-the-bacon best, but in the wee mad hours of the General Assembly's finale in Richmond early Sunday morning, everything clicked into place for Northern Virginia: the local delegation members held fast resolutely through the night, Gov. Charles S. Robb worked the phones smoothly on their behalf, the leadership read and delivered all the right signals and-- out came new money for Metro as part of a strong rails-and-roads/gasoline tax package.

As State Sen. Adelard L. Brault (D-Fairfax) put it unmildly but on good authority, "Northern Virginia has had the greatest accomplishment today that I've seen in the 17 years I've been down here." The result, or "bottom cash," as Sen. Brault called it, is $14 million a year in state subsidies for Metro plus recognition by the state of a financial commitment that should satisfy federal demands for evidence of a "stable and reliable" source of money for Metro from Virginia.

Some Fairfax County officials voiced concern yesterday that the language agreed to in Richmond might not guarantee relief for operating costs of Metro as specifically as had the statute that would have added 2 percent to Northern Virginia's regional gasoline tax come July, but which was repealed in favor of this latest state package. But Sen. Brault, credited by all as a pivotal figure in these negotiations, tells us this is only a technicality that should not cause any difficulties. We hope this is the case.

And if all the talk of unprecedented state kindness to Metro and the northerners it serves seems a little grating to those lawmakers from around the state who prefer to talk about highway projects, they should fret not: thanks to the outcome, Virginia has a financially and politically sound, balanced transportation program--thoroughly defensible as the only way to tax and serve residents fairly throughout the state.

Del. Warren G. Stambaugh (D-Arlington), another key player in the negotiations, joined Sen. Brault and other legislators from various parts of the state in crediting Gov. Robb with a smooth performance on the phones--"arm-twisting in a gentlemanly fashion," as Del. Frederick H. Creekmore (D-Chesapeake) described it. There was bipartisan cooperation, too, with 19 of 21 Northern Virginians (only Republicans Kenneth B. Rollins of Loudoun and Harry J. Parrish of Prince William refused to vote for the gasoline tax) sticking together for a change. Similarly the leadership in both houses moved well and upheld commitments in the critical hours.

So whatever other shortcomings or disappointments may be left in the emptied aisles of the chambers this week, this session of the General Assembly can be deemed productive in a most important way that should benefit every region of Virginia--and that has not been exactly a trademark of sessions past.