Metrorail would extend its weekend hours past midnight, currently the earliest closing time among the country's major transit systems, under a proposal likely to be considered in September by the agency's directors.

D.C. Council member Jim Graham (D-Ward 1), a Metro board member who has been advocating the later hours, said he is confident he can gain majority support for running the trains at least until 1 a.m. on Friday and Saturday nights and hopes to win consent for a 2 a.m. closing. If the agency adopts the plan before autumn, the new hours could take effect by the end of the year.

The proposal has been widely applauded by restaurant and movie operators as well as by many weekend revelers, who might cut their evenings short to catch the last train or linger longer in nightclubs and bars and drive home drunk.

"Bars close at 2. That's when Metro should close. No, 2:30. It's a safe way to get home," said Jason Cassano, 27, of Northwest Washington, who arrived at the Woodley Park-Zoo station last weekend moments ahead of the final train. "I'm from New York. I'm used to the subway running."

With demand for after-midnight Metro service projected to be considerably lighter than earlier in the evening, a study completed this month by the agency showed that passenger fares would pay for only one-third of the cost of extending weekend service until 2 a.m. About 7,200 new trips are anticipated each Friday and 7,600 each Saturday. That would leave a $2.7 million annual shortfall to be covered by subsidies from area governments.

But Graham and other advocates of the longer hours say the expanded service could have broad economic benefits, not only for the district's bustling nightlife around Adams-Morgan and U Street NW but also for planned entertainment development in Gallery Place downtown and in Ballston and Silver Spring. Longer hours could also reduce drunken driving and ease late-night traffic congestion.

"If people are out Friday and Saturday night, they're probably drunk or otherwise altered and shouldn't be driving," said Andrew Wiley, 24, of Greenbelt. "This idea would make it possible just to go out and have a good time Friday and Saturday night."

Hand in hand with his date, he strolled along the sultry strip of clubs in Adams-Morgan late Friday, past table after sidewalk table heavy with bottles and cans and pints and plastic cups of beer. Heat still radiated off the facades of the ethnic restaurants, more than four hours after the sun had set. A chain of brake lights stretched for blocks along southbound 18th Street, disappearing down the hill, melting into the steamy mist.

"Finding parking is ridiculous around here," said Wiley's companion, Melissa Horvitz, 21, of Greenbelt. "If Metro went after 12, it would help us out a lot."

Since 1978, two years after Metrorail opened, the trains have run until midnight on Fridays and Saturdays as they do on weekdays. In New York, Chicago and Philadelphia, transit agencies operate around the clock. Even smaller systems run later: Atlanta closes at 1 a.m., while Boston and San Francisco close at 12:45 a.m.

The main reason Metro ends service relatively early is to perform maintenance on the tracks, signals and other equipment. Unlike older transit systems that have express and bypass tracks, Metro operates with only two tracks. This often requires train service to be suspended so that power can be cut while work is done, according to Rod Burfield, the agency's director of business and financial planning.

Extending weekend hours until 2 a.m. would reduce the time for maintenance by 12 percent, Metro's study found. That would not hamstring the system's upkeep but would require adding an extra maintenance crew during the remaining hours and a $1.1 million investment to outfit the workers with trucks and other equipment.

Burfield said the system would be hard-pressed to extend its weekday operations to 2 a.m. as well. But Metro riders as well as entertainment executives said longer weekend hours remain their top priority.

"There's no reason Metro shouldn't be open till 2 or 3 a.m. on weekends," said Charley Stoessel, marketing coordinator for AMC Theaters in the Washington area.

He said the extra hours would especially benefit the cinemas at Court House in Arlington County and at Union Station, where late shows are timed with the train schedules in mind. Extended Metro hours would also encourage the planned development of theater-and-retail projects, including a 22-screen complex at Gallery Place and a 24-plex on Duke Street in Alexandria, Stoessel said.

Likewise, enhanced train service could improve the chances for the development of a multi-screen theater for the District by Loews Cineplex Entertainment because of existing limits on available city parking, according to Marc Pascucci, senior vice president for marketing. He said later weekend hours would primarily benefit the more sophisticated moviegoers who frequent his company's Odeon Cinemas, often combining dinner with a late film.

The prospect that patrons could dally over their meals, perhaps indulging in dessert, sounds sweet to restaurant owners. "If people are confident they can stay out later without their transportation turning into a pumpkin, they will likely stay longer and take full advantage of menu choices," said Eric Peterson, president of the Restaurant Association of Metropolitan Washington.

On 18th Street, where the late-night blare of car horns competes with the waves of music crashing from the clubs--rock and reggae; salsa, soukous and swing--Courtney Smith said Metro's early curfew was cramping her dancing style. "Longer hours would make a big difference in my life," said Smith, 23, of Northwest Washington. "There's no good club or good bar that starts going before 11. You easily stay out past midnight."

Lynne Ostrer, 26, would have preferred to remain at least an hour longer at a party in Woodley Park but slipped out to catch the last train home to Pentagon City. "It's safer to take Metro than to get in a car with people who have been at a party with you," she said, waiting on the platform of the Woodley Park-Zoo station.

But on a nearby bench, Linda DeBerry, 47, of Silver Spring, sounded a rare note of dissent on extending the subway hours.

"I don't think that many people are out that late at night," she said, returning from her job at a nearby bed-and-breakfast. "And if they are, it could be for not-very-good reasons."