Metro's financial history, a series of Houdini-like escapes from peril, is in the middle of two more crises that threaten to delay the start of construction this December on the last 40 miles of the subway system.

Like many of the earlier crises, the new ones pit neighbor against neighbor.

Maryland, one of the three big Metro partners, has declined so far to take actions that are needed to free federal construction dollars for the new work.

Fairfax County, one of eight smaller Metro partners, has taken a parochial dispute with tiny Falls Church and escalated it into a problem that could delay approval of local construction dollars.

Both federal and local money must be in place before contracts can be awarded. The first major item to be affected, according to Metro officials, is the $27 million needed to complete the long-awaited Metro crossing of the Potomac River at the 14th Street Bridge that would connect the Pentagon station directly with the L'Enfant Plaza station.

The more serious problem appears to be the Maryland situation. Last fall, Metro and the federal Department of Transportation signed a painfully negotiated agreement that arranged for the retirement over 30 years of $1 billion in bonds sold to build Metro. The federal government will pay two-thirds of the cost. Metro, through contributions by its local partners, will pay one-third.

To guarantee the local share, the federal government required that each of Metro's three major partners -- Maryland, Virginia and the District of Columbia -- designate Metro as the recipient federal operating assistance. That amounts to about $25 million in the current fiscal year. If there were a default by Metro on a bond payment, the operating aid would in effect be withheld by the federal government.

Virginia and the District of Columbia set about to designate Metro as the recipient of the money. Maryland has declined so far and has written a letter to the federal government requesting, in effect, a new agreement.

Although federal officials have said on several occasions they will enter only one agreement -- with Metro alone -- DOT spokesman Bob Holland said yesterday Maryland's letter had not been received so could no be answered. "Haven't we been through this before?" Holland asked.

Larry Saban, the Maryland Department of Transportation representative who closely follows Metro affairs, said in a recent interview the Maryland position is based on the feeling that for "more appropriate control" the federal aid funds "should remain in the hands of Montgomery and Prince George's counties."

Saban said yesterday "it is a little premature to determine what our governor's action will be" if the federal government restates its position that there be only one contract, and that with Metro.

Metro Board members from Virginia and D.C. grumbled about problems with what they thought was a signed agreement, but adopted a wait-and-see approach.

"I think you're really opening a can of worms," Fairfax County board member Joseph Alexander said to Saban. "You're talking about serious holdups" in the construction program.

The fairfax County-Falls Church problem stems, in part, from a lengthy debate over whether the Orange Line from Rosslyn to Vienna will have West Falls Church as a temporary end-of-the-line. Falls Church insists that the neighborhood cannot stand the added auto traffic that would result. It proposes a rescheduling of construction so the entire Orange Line segment from Ballston (to open Dec. 1) to Vienna will open at the same time.

Fine, Fairfax County has said, but Metro must provide a money-back guarantee that there would be no more than a six-month difference between a West Falls Church opening and a Vienna opening and that the entire Orange Line would be in operation by 1985.

Fairfax County is seeking that guarantee through an amendment to a regional contract that has already been signed by seven other local governments. Just where Metro would find the money for a refund is a question no one can answer.

Metro officials and Fairfax County board members laid the dispute aside during the recent county board election campaigns, but must resolve it soon to the satisfaction of the other Metro partners if local money is to be available.