THOUGH FINAL court approval to build a new Wilson Bridge may take a while, important moves are afoot to clear a large second obstacle: construction money. The U.S. Department of Transportation is proposing $600 million more for a financing package that would bring the total federal share to nearly 80 percent of the $1.9 billion price tag. The rest would come from Maryland, Virginia and District shares.

The additional $600 million would be spent in equal installments over four years starting in 2004. Regional House and Senate members have pledged to push hard for congressional agreement, citing the phased payments as a workable approach. More than a little federal interest is involved: The existing bridge, owned by the federal government, is crumbling. "If that bridge were to fail from the standpoint of safety," Virginia's Sen. John Warner warned, "it would be paralytic to the operation of government in the nation's capital."

The Transportation Department also has moved to appeal an order by U.S. District Judge Stanley Sporkin to halt construction of the new bridge for a more extensive environmental review. Secretary Rodney Slater said his department will argue that it met requirements with its initial review. Fairly, the administration has asked the court to hear the appeal as early as this fall.

If the money is approved and the court appeal succeeds, construction could begin in the fall of 2000 and finish in 2004, officials say. In the meantime, the department is moving ahead with additional environmental-review procedures in case the ruling stands. No one is advocating shortcuts that would undermine federal environmental safeguards. All that supporters of the replacement -- the federal government, the two states, the District and every participating local government -- seek is the most expeditious processing possible.