Virginia officials, faced with decisions on state contributions to the construction and maintenance of Metrorail, are calling the transit system a good idea that was oversold as a solution to traffic congression and underestimated as a burden on taxpayers.

"There was an overselling of what Metro would do on our side of the creek (on the Virginia side of the Potomac River)," Robert Lockwood, a state transportation planning engineer said. "A lot of people are backing away from those claims now, and there may even be some over-reaction in the other direction. What we need to do now, and what we are trying to do, is analyze the potential and weigh it against the costs."

Oscar K. Mabry, director of the Transportation Planning Division of the Department of Highways and Transportation, also says he sees a new cost-benefits analysis as the key to support of Metrorail in Virginia. "The thing was also oversold in terms of net income analysis," Mabry said. "It was presented as self-supporting. Now the question is, 'If you want this kind of service, how much are you willing to pay for it?'"

Despite the reservations about the rail network, Gov. Mills E. Godwin and his top transportation advisers emphasize that they continue to regard it as a necessary part of transportation services in the Washington area.

Aides to Godwin said in recent interviews that his policy toward Metrorail remains basically as he described it in a speech in Alexandria late last year.

He said then, "My position all along has been that a reasonable, feasible Metrorail system was a necessary part of the travel solution in this area, but it was not necessarily the complete and only solution.

"My own dilemma is that I must be conscious of the welfare of all Virginias," he said in Alexandria. "I must therefore ask myself to what extent I can ask them to help the communities of Northern Virginia with their local problem."

In 1976, at a time when he was saying that construction cost overruns and potential operating deficits threatened the feasibility of Metro, Godwin vetoed the General Assembly's appropriation for Metro construction aid. This year, he approved a similar appropriation when language was added giving the governor the right to withhold the $10 million until convinced that a feasible financing plan was developed for completion of the system.

Such a plan apparently will not be ready before Godwin leaves office in January. It cannot be developed until a study of alternatives to two Metrorail extensions in Northern Virginia - the Vienna and Springfield lines - is completed this fall.

The current study of rail alternatives is being closely monitored by state transportation planners, including Lockwood, who serves on the Alternatives Study Technical Committee.

Lockwood said that the state still is "taking a low profile" in the restudy, but added, "When it is completed, we will feel free to make a recommendation to our management" on the final shape of the Metrorail system in Northern Virginia.

"We are not only concerned with the capital costs," John E. Harwood, state highway and transportation director, said in an interview. "There has been a tremendous inflation in Metro's construction costs, but we know at some point a final limit will be set. We are more concerned now about building a system with such high operating costs that it could ruin the local governments up there."

"I guess they'll get all over me for saying this, but to some extent our job is to save them from themselves," he said.

Northern Virginia cities and counties are trying to recover two-thirds of their share of Metro operating costs out of the fare box but are still looking for alternatives to the real estate tax to pay for the other third.

Some of Virginia officials' reservations about Metrorail seem to flow from a feeling that cost controls on the mammoth project have been loose. Twice the state had to persuade federal officials that Virginia should not pay up to twice normal construction wages for highway work done in connection with Metrorail construction.

In the first instance, federal officials tried to impose higher rates for construction of a Metro underpass under Interstate Rte. 95, the Shirley Highway. "It was nothing but a box culvert like ones we have been building for years," Harwood said. "We couldn't see any reason for paying premium wages just because Metro was going to run through it."

Harwood and other Virginia transportation officials, however, said they think Metro's new general manager, Ted Lutz, has brought a new spirit of cost consciousness to the transit project. Lutz has personally visited Godwin twice since becoming general manager less than a year ago.

The state has contributed or promised about $130 million for Metro construction, most of it from state and federal gasoline tax revenues within its control. About half that amount has become available since an agreement was reached between the state and federal governments which gave federal approval to completion of Interstate Rte. 66 and sanctioned the use of some Virginia Interstate Highway funds for Metro.