By Matthew Hirsch

IF SAN FRANCISCO ever created a Register of Historic Misnomers, the Triangle Sandwich Shop would be on it. But no such list exists. That means no protection for the modest, five-walled Triangle, which stands in the way of progress on a busy corner of the developers' paradise known as Mission Bay.

By any account the Triangle has already surpassed its life expectancy. The diminutive, pentangular shop at the intersection of 3rd and 16th Streets still has its original Formica counters and a green backboard menu hanging from the ceiling. Food items seem priced for 1949, the year the restaurant opened. Long gone are many of its original habitués: blue-collar workers from local factories or the railroad and trucking industries. Many of those customers gradually faded away during the neighborhood's many economic transformations – leaving the Triangle behind.

Long before the dot-com development boom, San Francisco's eastern waterfront had already shifted away from its light industrial base. Teamsters and Hell's Angels used to rule this part of town, but the neighborhood's working-class roots have grown less and less detectable. The changes to the area will only become more evident as a result of two enormous modernization projects currently underway, the Muni Third Street Light Rail and a 300-acre redevelopment project by Catellus Development Corp.

So to say the Triangle is open for "business as usual," as a sign outside declares, is ridiculous. Business there has never been "usual." The Triangle has constantly been adapting to the changing world outside its doors.

Amid the dying remnants of the neighborhood's industrial past, the corner where the Triangle sits is busy again these days. Construction of the Muni light rail here is nearly complete, and the first few structures of Catellus's development project, including a UC San Francisco research campus, are beginning to take shape. Inside the restaurant's doors you'll find another sign of changing times: scientists and biotech workers are sidling up next to the working-class customers.

As industries rise and fall around the Triangle, the question is: How much longer will this neighborhood mainstay survive?

To give you an idea of what the Triangle is up against, take a bicycle ride up Third Street from the Embarcadero. Coast along the roughed-up sidewalk and keep an eye out for the Triangle on the right. Don't see it? You'll have to pass the big pile of dirt that dwarfs the building, which was tossed beside it by bulldozer operators working on the 2.65 million-square-foot UCSF campus next door.

Steven Head, whose mother, Judy, owns the restaurant and who has worked there since he was eight years old, insists it isn't going away anytime soon. That's because it doesn't matter where his customers come from: the Triangle has universal appeal, he said. New customers from the UCSF biotech building that opened in March aren't demanding California cuisine from the Triangle, Head told the Bay Guardian. Instead, they want root beer floats – something the regulars never order.

But something far more remarkable is happening inside the Triangle than the combination of soda and ice cream. The unassuming sandwich shop has unexpectedly become a cross-section of demographics: workers in blue-collar jobs are mingling with Ph.D.s in lab coats. One Monday morning last month, for example, a regular asked two of the first scientists working in Genentech Hall if it's true that the building's bathrooms are made of marble. The scientists gushed over how the building is much better than their old facilities in Parnassus Heights, no thanks to the original architect. This led to a general trashing of professionals who can't do their jobs. The guy next to them launched into a story about a bad experience he once had with a divorce lawyer. "Sometimes they forget that they're working for you," he said.

It's no secret that Catellus's plans for Mission Bay don't include the Triangle. If the developer's preference for large-scale development weren't already a clear indication – it signed early leases with Safeway, Borders Books, and Starbucks – its promotional guide to nearby amenities says it all. Catellus's dining and entertainment map on its Mission Bay Web site identifies many of the area's businesses but doesn't include the Triangle.

According to redevelopment regulations, Catellus, which owns the land on which the Triangle sits, can't close the Triangle only to replace it with a chain sandwich shop, like Quizno's or Schlotzky's. But the developers can tear it down to extend the UCSF campus over the Triangle's property, something they may do in the next phase of campus construction. Indeed, some construction plans show UCSF buildings on the site where the restaurant now stands.

The arrival of UCSF-Mission Bay may mean a battle over the Triangle, in some ways the last holdout of an almost unrecognizable past. It's hard to imagine that restaurant will actually prevail against Catellus or the greater forces of "progress." That's why artist Anthony Holdsworth depicted the Triangle in his painting Vanishing Landscape three years ago. "He thought every day they were going to take a [wrecking] ball to it," Head said of Holdsworth. "He thought they were replacing Americana with concrete."

Catellus's plans for Mission Bay stalled when the economy headed south two years ago. While the development giant has no immediate plans to build on the Triangle's property, the shop's fate has turned into a waiting game for Head and his family. Head told us he thinks the company is waiting for his mother to die before moving in on her business. "She's been here 54 years. How would you like to have to throw her out?" he said.