HE engineering firm of Weidlinger Associates Inc. is a warren of partitioned offices awash in blueprints and maps and grown- up people in conservative dress.

Then there is Brian M. Wiprud, the utilities specialist. Or, as he prefers to think of himself, for he is of playful and literary bent, Brian Wiprud, manhole detective.

He is dressed more like an East Village artist than an engineer; a funky long-sleeved white shirt worn over a faded blue-green paisley shirt. His blond hair is combed in a pompadour like Tintin, the children's book hero's.

This makes sense, for Mr. Wiprud, 40, is not an engineer. His college degree was in film, and for pleasure he goes fly fishing and writes detective novels. He is the inventor of the hot pink Zsa Zsa lure, available on his Web site (wiprud.com), as is a chapter from his novel, "Sleep With the Fishes."

Still, there is no question of Mr. Wiprud's underground expertise. He was called upon a few days after the attack on the World Trade Center to try to find an underground rescue route. He has been making a comprehensive map of the subterranean area that will show the utility and sewer lines and subway tunnels as they were before the attack. He has pulled together maps made by the telephone company and the Works Progress Administration in the 1930's and walked the rubble of ground zero, mapping manholes.

The attempt to find a rescue route was particularly difficult. Some records were in buildings that were closed. In one instance, Mr. Wiprud found himself walking up 11 flights, wearing a gas mask. And finally, the attempts to find a rescue route through a 19th-century sewer pipe or abandoned subway tunnel failed anyway.

"There are old sewers, installed around the end of the Civil War, that might have been large enough for somebody to get through, 4-foot by 2-8, but they probably would have dead-ended," Mr. Wiprud says.

A combination of cinematic and water-treatment references is not uncommon in conversation with Mr. Wiprud.

"Most of the city sewers are too small for people to go though. It's not like `The X-Files,' where people are chasing monsters through the sewers, or the sewers of `The Third Man' where they're oversized and huge. We do have sewers like that, but they're so inundated by water you can't go down there."

Some cases from the files of the manhole detective:

Scoping out the refrigerant lines at 1 and 2 New York Plaza; trying to find a way for a water main to get from First Avenue and 23rd Street to Franklin D. Roosevelt Drive and 15th Street; finding a way for Time Warner to get its cable across the Manhattan Bridge. That one was tough because the manhole detective had to crawl along the underside of the length of the bridge. And he has a fear of heights. Suspended 120 feet up, he watched the loose change fall out of his pockets into the river. The pleasures of the job were as they always were and not unlike writing detective fiction: solving a puzzle, connecting the dots.

SO it goes in the map of life. Sometimes you connect the dots, sometimes the dots connect you. Mr. Wiprud did not plot a life route that would involve the utility lines of underground New York. He wanted to be a filmmaker. But we skip critical points.

Mr. Wiprud grew up in Washington, D.C. His mother was an editor for the Department of Education; his father, "gregarious and irresponsible," was a tax lawyer for the Justice Department, and he drank. "What's the best way of putting this?" Mr. Wiprud asks. "He died after a series of strokes and drinking and pills and stuff. He told a mean story, though. They were divorced when I was 15."

Mr. Wiprud graduated from St. Albans prep school in Washington and New York University film school. Then came the matter of getting work. He did lighting and grip work for small filmmakers and made ends meet selling newspapers at the Brooklyn-Battery Tunnel.

He was a college graduate who worked as a paper boy?

"It's Paper Boy when he still lived in Smallville," says Mr. Wiprud. "When he comes to Metropolis, it's Paper Man. The day David Niven died was a banner day for me. Everybody wanted to read about David Niven."

Mr. Wiprud got into his field of expertise when an engineering firm required footage of sewers. Mr. Wiprud did not do the filming himself. The cinematographer was a robot on treads, with a rotating camera and lights. Mr. Wiprud sat in a mobile TV studio and made certain the robot was getting it right. That led to reading and mapping manhole covers and underground utilities. Often, in addition to studying maps, Mr. Wiprud must climb down a manhole or direct a dig.

As for those living creatures that are the bane of underground workers, they do not trouble Mr. Wiprud. "I have no problem with the rats," he says. "I think of them as squirrels. They're a little curious. Sometimes they follow you around. I see them now and then when I'm videotaping. They're usually sitting right at the outfall from the restaurants, eating the salmon carpaccio."