A fierce rush-hour rainstorm was pounding the roof of the blue and gold DASH bus as it pulled out of the Braddock Road Metro station and splashed down its route through Alexandria.

As the driver navigated the bus through the soaked and sluggish traffic, Royce Drake relaxed in the back row and explained why he rides DASH.

"It's a good system. I enjoy riding it," Drake said, adding, "I'd like to see a few more buses in the evenings."

Drake's comments are echoed by other riders, who praise the city's six-year-old system but want more service, and by DASH managers, who are struggling to keep pace with Alexandria's rapid growth.

"Ridership is expanding so greatly, we're having difficulty keeping up," said DASH general manager Sandy Modell.

DASH's fleet of 19 buses carry more than 5,000 riders a day on four routes serving Old Town, the West End and the neighborhoods between the Pentagon, Braddock Road and King Street Metro stations.

That leaves many rush-hour riders without seats, said Bonnie Agnell, who had beat the crowd by catching the 4:50 p.m. bus from the Pentagon to her home near Park Fairfax.

"They need to get larger buses; people are always standing," Agnell said.

Two of DASH's buses have 42 seats each, with a capacity for about 60 people; the rest have 31 seats with a capacity for 50.

Other riders would like more frequent service and more routes.

"I just wish there were more of it," said Jerry Hines, a systems analyst who rides DASH to the Pentagon Metro station and then rides the subway to his job near the Federal Triangle station, all for $1.80 each way at rush hour.

"I'd like to use it more for just getting around," Hines said.

That kind of response is both gratifying and worrisome to DASH managers, who are working to expand the system.

DASH has ordered nine more 42-seat buses, all equipped with wheelchair lifts, to begin service to the Van Dorn Street Metro station when it opens in April.

The system plans to order five more buses this month to add a second route and more frequent service in the Eisenhower Valley.

"People will only use the service if it's frequent and convenient," Modell said.

DASH started service in March 1984 -- three months after Metrorail was extended from National Airport through Alexandria to Huntington -- with several goals, Modell said.

The city created DASH to improve access to the new Metro stations and to replace some of the Metrobus routes that were scrapped at the time.

Planners also saw DASH as a means to improve circulation within the increasingly congested city and serve new developments.

Alexandria officials, like Fairfax County officials who created the Fairfax Connector bus system, also were worried by rising Metrobus costs and decided to save money by substituting their own service where appropriate.

For example, Metrobus continues to serve the heavily traveled Mount Vernon Avenue and Duke Street corridors, which require bigger buses and higher frequency than DASH could provide economically, Modell said.

At the same time, the flexibility of a small system meant that last month DASH could quickly add six trips a day to serve summer school students when the ridership numbers jumped from an average of 4,900 passengers a day to 5,500 a day.

DASH was created to be "responsive to the needs inside Alexandria," leaving Metrobus the role of providing service to other jurisdictions, Modell said.

DASH service is provided by Alexandria Transit Co., a nonprofit public corporation owned by the city and run by a seven-member board of directors.

The name DASH was the winning entry submitted in the city's "name that bus" contest.

The acronym was suggested to stand for Downtown Alexandria Shuttle, but that part was abandoned because the system serves more than downtown, Modell said.

DASH fares -- 65 cents for most trips, 95 cents for trips to the Pentagon -- cover about half the system's costs.

The city makes up the difference, spending $862,000 to subsidize the service in the fiscal year that ended June 30, 1989, the last year for which firm numbers are available.

The subsidy for the fiscal year that just ended is projected to be $978,000.

Most passengers appear to think they're getting their money's worth.

Stephen French, an engineer who rides DASH daily from his doorstep to the Pentagon in 15 minutes, said, "Overall, the system is exceptional."