BRUNSWICK — Just days after the local landmark Fat Boy Drive-In posted a “for sale” sign on its signature marquee, agent Victor Tedford said the listing is “on fire,” with more than a dozen people already expressing interest in purchasing the property.

The Bath Road restaurant is listed at $1.15 million, which Tedford, an agent with Magnusson Balfour, said includes the business and a number of tangible and intangible assets, including decades’ worth of loyal customers.

Fat Boy opened in 1955 when drive-in diners were in their heyday, and owners have been serving up burgers, BLTs, onion rings and nostalgia ever since.

John and Pauline Bollinger and Joe and Jennie Burton ran Fat Boy every afternoon, seven days a week from March through October for 20 years until John Bollinger died in 1978, according to the diner’s website.

Current owners Ken and Jeanne Burton purchased it from Ken’s father, Joseph Burton, just a few years later in the mid-1980s and have changed little in the past 35 years.

Burton worked at his father’s restaurant in high school and then off and on in his adult life before he and his wife ultimately bought the business. Their two children and five grandchildren have all been Fat Boy employees, making this a family affair for generations.

“I hope somebody will keep it the same,” Burton said. “I’d love to be a customer there someday.”

After more than 30 years and working “24 hours a day,” he said he and his family are “all burnt out” and it was time to move on.

“I’m 72, almost 73. I want to relax and enjoy my age before something happens to me and that’s just part of life,” he said.

Burton said good food, good service and good prices have kept the restaurant going even as other drive-in diners have shuttered and fast food chains like McDonald’s have nudged many family-owned businesses out the door.

“It had an atmosphere you can’t fake,” said Doug McIntire, a Brunswick native (and a one-summer Fat Boy employee).

“It was the kind of place your parents took you to after ball practice, it was a family thing,” McIntire said. “Then when we were teenagers it was the spot everyone hung out. … It was Brunswick comfort food.”

But it wasn’t just the food and atmosphere that kept Fat Boy as a “community staple.” It was also the Burtons themselves.

“The Burtons were always warm and welcoming,” McIntire said, recalling a night one summer when his boss went out back to feed a family of raccoons who, like everyone in town, had been frequenting Fat Boy for generations.

According to Brunswick writer David Treadwell, Brunswick is unusual in its lack of franchises. “Most places are family-run,” he said, noting that Maine Street is home to just one or two chains.

“I can’t imagine what type of place could come along that could be a better way to go (than Fat Boy),” Treadwell said. “Any new owner would be stupid to change anything.”

McIntire agreed, adding that he thinks there’s some fear a “hipster with a dream” will try to come in and rejuvenate the beloved menu with “craft burgers and artisanal frappes.”

To Treadwell, the food (again, the onion rings came up) and the “old summertime 1950s thing” kept Fat Boy afloat. “There’s that tradition and nostalgia,” he said, adding that the annual August sock hop was always mobbed. When Treadwell interviewed Burton for a story in 2002, the owner estimated that the event drew between 500 and 700 people for ’50s music and dancing.

Fat Boy struggled to attract enough summer help in recent years, ending the season early in 2016 with roughly half its usual staff.

“It’s something everyone took for granted always being there,” McIntire said, calling the sale a “big loss for the town.”

Tedford said that ideally, the new owner will be someone “motivated and energetic,” who is looking to keep up the traditions that have made Fat Boy “successful for decades.”