BALTIMORE -- Joe Gillis (William Holden): "You're Norma Desmond. You used to be in silent pictures. You used to be big." Norma Desmond (Gloria Swanson): "I am big. It's the pictures that got small." -- "Sunset Boulevard" (1950)

The Senator Theatre is still big.

In a world of mall-based, shoe-box movie houses, Baltimore's 900-seat art deco showplace offers an old-fashioned moviegoing experience, from plush seats to real butter on the popcorn.

Built in 1939, the year film historians consider the apex of Hollywood's power and glamour, the Senator has blossomed from neighborhood movie house to "palace" as it takes on special significance in an era when older theaters across the nation are dying. Its curved, glass-bricked facade, lighted from behind by yellow, green and pink neon; its oval foyer, embellished with a kitschy, circular mural depicting the history of visual entertainment, a terrazzo floor and 30-foot-high ceiling; its huge auditorium with a 35-foot-high ceiling -- all make it truly palatial compared with the typical cinemas of today.

It is a rare surviving example of the neighborhood theaters of filmdom's golden age, and as such it is on the National Register of Historic Places.

"Going into the Senator is like stepping back 40 or 50 years," said Robert Headley, a research linguist for the federal government who lives in University Park in Prince George's County and is at work on his second book about motion picture theaters.

"The Senator is the best neighborhood theater in this area . . . . It's the only one that has the class and ambiance of the neighborhood theaters of '40s and '50s . . . . They actually put together a real show with cartoons and all. It's really terrific," said Headley, adding that he and his wife travel to Baltimore just to see films at the Senator.

Keeping the Senator going is the 16-hour-a-day passion of Thomas A. Kiefaber, grandson of the man who built the theater. "What we're doing here is a high-wire act without a net," said Kiefaber, 37. "So far, we haven't tripped and fallen."

Actually, Kiefaber has compiled an impressive record for the Senator since he and a partner, J. Hollis Albert III, managed to put together a $2 million financing package in December 1988 and buy it from Durkee Enterprises, the firm founded by Kiefaber's maternal grandfather, Frank Durkee Sr., in 1916. The company had planned to sell the Senator with most of its other, multi-screen Baltimore holdings, but Kiefaber, who once had shied away from the family business, hustled to take over the movie house where he fondly remembered spending countless hours as a youngster.

Capitalizing on the Senator's single-screen anomaly in a business now characterized by "twinned" or "tripled" old theaters and new multi-screen complexes, Kiefaber has accentuated its 40-by-25-foot screen, six-track, multi-channel sound, private party rooms and other amenities. Kiefaber and Albert even landed the Senator a starring role -- playing itself, of course -- in director Barry Levinson's next celluloid paean to Baltimore, his home town.

The new film, "Avalon," is set to have its world premiere at the Senator next fall, when patrons will have the eerie experience of sitting in the theater and watching a scene in which actors dressed in 1940s attire sit in the Senator and watch a movie. "It'll be like looking into an infinity of mirrors," said Kiefaber.

Levinson's other Baltimore films, "Diner" and "Tin Men," also had premieres at the Senator, as did John Water's "Hair Spray" and "Cry Baby," and other Baltimore-made movies, "The Accidental Tourist" and "Her Alibi."

Kiefaber also has booked classics such as "Gone With the Wind" and "The Wizard of Oz" (both made in 1939) and fought for the city's premiere showings of such blockbusters as "The Hunt for Red October," based on the novel by Baltimore-born Tom Clancy.

The Headleys are not the only members of the Senator's new wave of patrons who come from the Washington area, Kiefaber said.

"We've noted that we're giving more and more directions to people who call us from farther and farther away," he said. "We get calls from up near the Pennsylvania line, down to Annapolis and even over on the Eastern Shore."

"We're becoming a regional destination for really discerning moviegoers."

The Senator's current successes, however, do not assure it a happily-ever-after future. As a single-screen theater, the Senator is especially vulnerable to a rise or fall in ticket receipts.

"We're succeeding in terms of staying just ahead of the economic forces that have put most single-screen theaters out of business," Kiefaber said.

Preserving the Senator as a single-screen house relies heavily on Kiefaber's plan to build two smaller movie houses this year on adjacent property.

With all the balls he has to juggle, Kiefaber rarely enjoys the Senator as a theater, the way his patrons do. But once in a while he settles into his favorite seat -- midway back on the aisle at the right -- and becomes part of the magical movie triangle that old screen siren Norma Desmond evoked at the end of "Sunset Boulevard":

"Just us, and the cameras, and those wonderful people out there in the dark . . . . "