Trustbank Savings F.S.B. of Tysons Corner, the area's third largest savings and loan association, was seized by the federal government yesterday, after a string of money-losing quarters drained its financial resources and left the S&L barely solvent.

Trustbank, formerly known as Dominion Federal Savings and Loan Association, will be open for business today as usual and its 153,000 accounts continue to be insured up to $100,000 by the government.

The Office of Thrift Supervision (OTS), which oversees the nation's savings and loans, said it took control of Trustbank because it was "operating in an unsafe and unsound condition." After seven consecutive losing quarters, the S&L was left with $19 million in capital, far below the amount required to protect the federal deposit insurance fund from losses. Trustbank's assets, which totaled $1.8 billion, exceeded liabilities by $2 million.

Trustbank is the largest savings institution in the metropolitan area to fail since the Great Depression and it is the second local savings and loan to be taken over by regulators in a year. In August, federal regulators took over United Savings Bank of Vienna.

The takeover of Trustbank, which operates 38 branches in the District and Virginia, follows a long history of financial turmoil and risky lending practices under its founder and chairman, William L. Walde. He gained national attention in 1988 when his S&L was sued by Penthouse International Ltd. over a loan to Penthouse publisher Bob Guccione for a casino.

Walde, a hard-charging real estate investor who helped establish the S&L in 1974, could not be reached for comment yesterday.

Walde's S&L also lent millions of dollars to Equity Programs Investment Corp., a Maryland real estate tax shelter partnership that went bankrupt in 1986, leaving scores of angry investors empty handed. The EPIC loans cost Trustbank millions of dollars.

Throughout the 1980s, these problems and Trustbank's aggressive push into commercial real estate lending repeatedly brought down the wrath of federal regulators.

Several times, they placed the S&L under strict supervisory agreements aimed at shoring up its bottom line.

The last such agreement was signed less than a year ago.

Trustbank, though, was unable to improve operations. In the quarter ended Sept. 30, Trustbank reported $116 million of loans that were in default or no longer paying interest, most of those on commercial real estate. This level of problem loans was six times greater than Trustbank's capital.

Last month, the OTS rejected Trustbank's formal plan outlining how it would improve its capital position, the first public sign in months that regulators were unhappy with Trustbank's progress.

The OTS said yesterday Trustbank's "aggressive thrust into risky real estate lending ... was a major contributor to the thrift's problems."

After stepping in at about 3:30 p.m., the OTS changed the name of the thrift to Trustbank Federal Savings Bank and appointed Jack R. Crigger of the Resolution Trust Corp., the agency created to handle failed S&Ls, as conservator to manage Trustbank's affairs.

Branches remained opened for business until 6 p.m. yesterday as employees were told of the takeover. Government officials said the thrift's 900 employees, who will retain their jobs under the conservatorship, reacted calmly. Customers at the S&L's headquarters branch on Leesburg Pike were also unfazed.

The RTC will try to sell Trustbank to a private bidder. If a buyer cannot be found, however, the agency can close Trustbank, pay off insured depositors and sell the thrift's assets.

Staff writer DeNeen L. Brown contributed to this report.