DON'T LOOK NOW, but the powers that be apparently have agreed on a way to rescue the Great White Elephant on Capitol Hill. This is the project known to old-timers as Union Station, to newcomers as the National Visitor Center and to any taxpaying American as a hideously expensive monument to bureaucratic waste and indecision. Word at the week's end was that the Interior and Transportation departments and the House Public Works Committee are ready to go with a proposal to finish repairing the structure; to move the trian terminal back toward its original sport; and to do something about that imposing skeleton of a garage that dangles in the breeze up there. The plans is by no means perfect. But the meter on this ride has been running at a devastating clip, and right now, relief is essential.

First, there isn't any argument about the need to make repairs. As for the train terminal, the tracks would be extended closer to where they used to end before a "new" station was built and promptly outmoded. No longer would baggage-toting passengers face an umpteen-mile-long trek to and from civilization; instead of staggering through a vast wasteland reserved for nonexistent services, travelers could get help in a visitor center taking up half that spaces. That makes sense-and never mind what they ever do about that big pit up front where the slide screen is sunk.

The garage, which was last proposed to accommodate about 1,400 vehicles, probably won't serve any great purpose-for if things run true to form, people who work on Capitor Hill will find a way to beat the system and take over the visitors' spaces. Besides, there's already a fine, expensive subway system running right through the place. An argument over completion of that part of the project should not be allowed to undo this latest agreement, for every month's delay adds to the cost.

Similarly, there seems to be some difference between the House committee and the administration over which department should run the visitor-center part of the complex. The bill introduced Friday would leave the center under Interior, with DOT running everything else. The administration would prefer it all under DOT. Frankly, the visitors won't much care. The important thing now is not to let this tedious but necessary rescue effort collapse as one did at the end of the last Congress.