GONE ARE the days -- at least for a moment or two -- of high financial drama at Metro, when the subway network for the national capital region would be hanging by a political thread somewhere between the Capitol and the White House, with every last inch of track dependent on some skinflint's change of heart. It isn't that Metro is rolling in dollars; but it is rolling around more of this metropolis every year -- with strong local support, a steady level of fares and reasonable federal financing to complement unflagging local and state commitments. The subway system is doing one other big thing too: moving millions of people around -- and building that long-awaited Green Line in town.

Officials announced last week that Metro will not seek fare increases from its rail or bus riders, but will ask local governments to help underwrite its operating budget. If the proposal is approved by the Metro board and ratified by the local governments, this would be the fifth consecutive year without a fare increase. The idea is to keep on attracting those who do ride and to entice others to do so. Obviously subsidies shouldn't be allowed to grow too large, but neither should a transit system be graded by its ability to turn a profit. Metro General Manager Carmen Turner estimates that without a fare increase, rail ridership could increase by nearly 7 percent over the next year.

Fares do account for a good portion of revenues anyway; Metrorail is expected to collect 73.2 cents from riders for each $1 of costs, up from 71 cents this year; and the bus system is expected to take in fares yielding 33.8 cents for each $1, down from 36.9 cents this year. Combined bus and rail fares should amount to 52.2 percent of costs -- considered a reasonable share.

Congress, meanwhile, has clipped a bit from the fiscal 1987 appropriation for construction, but has approved enough to allow completion of the Green Line spurs to Greenbelt and Anacostia. The allocation is more than the Reagan administration recommended; and as usual, Rep. Frank Wolf of Virginia, a member of the House Appropriations Committee, was instrumental in the delivery. So, too, were Rep. Steny Hoyer and Sen. Barbara Mikulski.

Metro isn't accustomed to this kind of intelligent, continuing support. The people who have waited as long as any others for a piece of the subway action -- the transit-dependent residents along the Green Line -- deserve this good fortune.