When Bonnie Parker – who was not yet a notorious outlaw but only a waitress in a bad marriage – worked at Hargraves' Cafe in the 1920s, the curiously curved building fronted a streetcar line in Old East Dallas.

Bishop Arts District

A streetcar passes Skillen's drugstore at Seventh Street and Edgefield Avenue in Oak Cliff around 1945.

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The space is now occupied by the Evans Grinding Co., where Walter Beaty, its owner and sole employee, sharpens knives and marvels that the structure has survived a surrounding building boom.

"It's an absolute miracle that they haven't torn it down and put up a 10-story building, but that's what's going to happen one day," Mr. Beaty said. "You've got to wonder 50 years from now what's going to be left around here."

His concern is shared by local preservationists, who fear for the future of the buildings that once clustered around streetcar and interurban stops in the early 20th century. Long after the tracks were torn up, scores of the small buildings remain, collectively forming one of the city's least-known urban treasures.

It's not as if they're hidden.

If you've ever dined at the San Francisco Rose, had a shake at the Highland Park Pharmacy or shopped in the Bishop Arts District, you've been in a former streetcar shop.

Those that have been fixed up, such as the clusters along Lower Greenville Avenue, have often been restored without knowledge of their past.

"I don't think anyone much has thought in terms of 'I want to preserve a trolley stop.' They fix it up just because they think it's a neat old building," said Virginia McAlester, Dallas author and architecture historian.

Other such buildings are derelict or altered beyond recognition. Some, such as the strip on Swiss Circle occupied by Mr. Beaty's shop, are in decline but still doing useful work.

Until very recently, all the shops were off the preservationists' radar.

They showed up for the first time on Preservation Dallas' annual most-endangered list just last month. Executive director Katherine Seale said they were included after a few of the shops appeared on a list of potentially historic buildings recently prepared by the city's planning department.

"People were aware of them, certainly, but we discovered we didn't know much about them," Ms. Seale said.

As a first step, the group has called on the city to survey the surviving streetcar shops and report on their condition.

In a city that often worries that it lacks distinctive character, the number of streetcar shops is unique in this part of the country.

"Houston and San Antonio haven't kept their streetcar shops. Dallas is the only city in Texas that has a collection left to a large degree," Ms. McAlester said.

Those three cities were among a handful that began the 20th century – the golden age of the streetcar – as medium-sized towns that exploded into major metropolitan areas in just a few decades.

Because Dallas' downtown was so small at the beginning of the era, the streetcar lines were built in areas that are now considered urban neighborhoods, such as the Peak Addition, Junius Heights and Winnetka Heights.

When the streetcar lines were torn up, one of the things that saved the clusters of shops was benign neglect, Ms. McAlester said. After World War II, developers looked beyond older neighborhoods and didn't try to replace the shops with newer construction.

The current movement of people back into the close-in neighborhoods poses an opportunity for the buildings – but also a danger that led Preservation Dallas to put them on its endangered list.

"We are concerned that with downtown and the surrounding areas reviving, it raises property values to the point that if a building doesn't have an obvious use, they're going to be torn down," Ms. Seale said.

City planners say the shops could fit in with their hopes for more walkable neighborhoods.

"My gut instinct is that with gas prices where they are, there will be more of these walking neighborhoods in Dallas," said David Schleg, chief of the city's long-range planning office. "These buildings could be sitting there waiting."

Among the most extensive redevelopment of streetcar shops is the Bishop Arts District in Oak Cliff.

And it is one of the few developed with full knowledge about its origins in the city's vanished streetcar system.

Jim Lake said that when his father bought up the area in the 1980s, "he was well aware of its connection with trolleys and researched it extensively."

But when the time came to market the district, he said, the arts theme was deemed more alluring than its link with urban transportation.

One issue in creating walkable neighborhoods is making sure that their businesses are not surrounded by parking lots. At the same time, businesses need to be accessible to a large number of people to be economically viable.

One solution, Mr. Schleg suggests, might be to bring in potential customers by streetcar.

That thought has occurred to Jason Roberts, president of the Oak Cliff Transit Authority, an organization that proposes reviving streetcar service to the Bishop Arts District.

The group is raising money for a feasibility study. Eventually, it hopes to run a streetcar line between Bishop Arts and other neighborhoods in north Oak Cliff.

"What we've seen in other cities is that development follows along a streetcar route," Mr. Roberts said. "And you don't have to widen your streets or tear down some buildings for parking."

The terms "streetcar" and "trolley" are often used interchangeably, but only "streetcar" is correct in this part of the country.

At least that's the contention of John Landrum, chief operating officer of the McKinney Avenue Transit Authority.

"Yankees call them trolleys; in the South, they're streetcars," he said. "Whoever heard of A Trolley Named Desire?"

Mr. Landrum acknowledged that his own promotional materials – including the logo – refer to the "McKinney Avenue Trolley."

"I have to get on our marketing department sometimes," he said.