Metro will receive $1.3 billion over the next eight years toward completing the planned 103-mile rail system under an agreement reached last night between the Bush administration and local officials.

Budget Director Richard G. Darman and Transportation Secretary Samuel K. Skinner told area congressional officials they would agree to the $1.3 billion, providing the federal share of construction costs will be 62.5 percent, while the local share is 37.5 percent.

Metro board Chairman Mary Margaret Whipple, of Arlington, said last night: "We had been faced with the threat of a veto from the administration for any reauthorization bill. For the administration to agree to any level of substantial funding is a very positive step for this region."

For 17 years, the Metro rail system has been financed with 80 percent federal funding and a 20 percent local contribution, so the agreement means that state and local governments supporting Metro will have to contribute millions of dollars more than they do now.

Officials could not estimate how much local governments will have to contribute. Previous estimates indicate the figure will be more than $300 million. Whipple said 37.5 percent "will be manageable."

The Senate and House still must vote on the Metro appropriation, which is a separate budget item.

The $1.3 billion will not be enough to complete the entire 103 miles; Metro had been seeking $2.7 billion over 11 years to finish the rail system. After eight years, Metro probably will return to Congress seeking additional money.

By then, Metro spokesman Beverly Silverberg said, the cost of completing the system will have risen.

So far, all but 13.5 miles of the Metrorail system has been completed or financed. Still to open are parts of the Red Line in Montgomery County, the Blue Line in Fairfax County and all of the Green Line in the District and Prince George's County.

Sen. John W. Warner (R-Va.) said that given the current budget climate in Congress, the agreement was a significant coup.

Local officials won another major concession from administration officials, who had wanted Metro to compete for federal money with the nation's other transit agencies. Because there is less money available from that source, and all transit systems compete, Metro would have received a smaller share.

Previously, the Bush administration, backed by some lawmakers, had argued that the Washington area, which includes some of the nation's wealthiest counties, should be treated more like transit systems elsewhere, some of which are getting more than half of their construction money from local governments.

But Darman agreed to keep the Metro appropriation separate from those for other transit agencies, as it has been in the past.