Servers on roller skates zipping by. Cars lining up a block deep and a line of people wrapped around the building. It was a busy day for the grand opening of the Sonic Drive-In in North Park.

Some die-hard fans waited in line just for a bite of their favorite foods. Fans such as Rob Nelson, a piano tuner who lives in North Park. Nelson, who grew up in Kansas has been a fan of the chain since the 1960s.

“I came here because I like their food. I like their shakes,” he said. “They’re natural. It’s really fresh ice cream, like I like.”

The burger chain took over Burger King’s location at 2829 El Cajon Blvd. in.

“This is our second Burger King that we’ve remodeled … and we’ve done real well — every site that we’ve remodeled,” said Max Gelwix, Sonic’s San Diego franchisee.

Sonic first came to San Diego in 2009, since then the company has expanded into seven locations in the county, including ones in Santee and Kearny Mesa.

What sets Sonic apart from the other burger chain is its carhop service, Gelwix said. The experience hearkens back to the golden age of the drive-through burger chains where servers, on roller skates, would bring food to customers’ cars in the drive-in stalls.

“Everyone of our customers get carhop service — it’s just a unique throwback that people enjoy,” Gelwix said. “No one else has drive-in stalls.”