The first morning of early-bird subway service yesterday, when Metro began running at 5 instead of 5:30, still wasn't early enough for some commuters.

By 4:45 a.m., about 70 people had gathered in the dark outside the Vienna/Fairfax-GMU Metro station, waiting for transit employees to unlock the large brown metal gates and let them board the first train.

"This lets me get out of work earlier," said Andrew Gude, a 44-year-old employee of the U.S. Fish and Wildlife Service. Gude woke up in his Vienna home about 4 a.m. and walked to the station. He said he planned to leave work about 3:30 p.m. The routine is made bearable by a 15-minute nap at lunchtime, he said.

Train 928 was a sleepy affair as it slowly chugged out of the Vienna Station and headed east toward downtown Washington. Some riders glanced at their newspapers or thumbed a paperback. Many gave in to the pull of sleep and the rhythmic rocking of the train and nodded off. There was no talking, no cell phone conversation, no sound except the low hum of the train.

From 5 to 5:30 a.m., 5,852 passengers passed through fare gates at the rail stations, Metro spokeswoman Cathy Asato said. The busiest stations were Shady Grove on the Red Line, Vienna on the Orange Line and Branch Avenue on the Green Line, she said. Transit planners have predicted that the extra half-hour will attract 1,700 new riders -- people who had not normally taken Metro.

Metro directors chose to open the subway a half-hour earlier partly as a way to ease the sting of the fare and fee increases that took effect June 28. But the decision was also a way to take advantage of the fact that trains were already traveling the railroad at that hour, dispatched from the rail yards to points across the system.

"The trains were already moving at 5 a.m.," said Robert J. Smith, chairman of Metro's board of directors. "We were putting them out on the lines, just not stopping to pick up passengers. Opening the stations at 5 a.m. just seemed like a fairly simple way to utilize the trains in a more efficient way."

The first trains were scheduled to depart terminal stations at 5 a.m., but passengers at interior stations had to wait an additional 10 or 15 or 20 minutes until those trains reached them.

Most of the passengers interviewed aboard Train 928 were government employees working on flextime schedules that allow them to be at their desks by early morning so they can leave by early afternoon.

Joe Fortune, a 43-year-old Centreville resident, said the 5 a.m. opening was ideal for helping him keep his 6 a.m.-to-2:30 p.m. workday as a computer technician at the FBI. "I think it's great," he said.

June Jones, who works at the U.S. Department of Transportation, said the earlier opening allows her to circumvent the morning and afternoon rushes. "I can be at my desk at 5:30 a.m. and leave work at 2 p.m. and miss all the crowds," said Jones, who lives in Warrenton.

Many who boarded Train 928 said they were happy to be able to find a seat. Under the old schedule, with its official systemwide opening time of 5:30, the first train would actually depart Vienna at 5:25 a.m. It was always crowded and sometimes standing-room only, said Karla Kase, 43, a Fairfax resident who works at the Department of the Interior. Kase woke at 3 a.m., worked out at her gym and then headed to the station. "I got a parking space, got a seat and it's one-fifth as crowded as the 5:25 a.m. train," she said.

John Crowley, who lives in Fairfax and works at the Federal Trade Commission, said he'd like to see Metro operate round-the-clock. "I'm from New York," he said, taking a break from a paperback copy of "The Main Enemy" as the train chugged alongside Interstate 66. "I'm used to jumping on the subway. I'd like to see it run all night."

But Metro's configuration makes 24-hour service impossible, transit officials say. Metro is a two-track railroad and uses the nightly shutdown period to perform regular maintenance on the tracks and trains. The New York system, which has four and sometimes six tracks, is able to run 24 hours because it can operate trains on some tracks while it shuts down others.

Metro shuts down for 51/2 hours on weeknights and four hours on weekend nights. "We've got to have some downtime to work on things," Smith said. "We've got to preserve some hours to be able to move vehicles and equipment on the system."

The earlier opening is projected to cost Metro $1.9 million a year, most of which goes to pay station managers and other personnel. But officials expect to collect $1.2 million in fares, resulting in a $723,000 subsidy from taxpayers to make up the difference.

Karla Kase of Fairfax rides the 5 a.m. train to downtown: "I got a parking space, got a seat and it's one-fifth as crowded as the 5:25 a.m. train."Mike Gonzales relaxes with a newspaper for his ride in from the Vienna/Fairfax-GMU Station. He says the day's first train used to be more congested.