It can be comfortable keeping a place somewhere along Highway 57, between Smyrna and Frog Level, in a recognizable but mythical South while you go about living your life in Central Indiana. Leastways, that’s what the 1989 cast of Indianapolis Civic Theatre’s “Pump Boys and Dinettes” has discovered over the past 20 years, playing two sisters running a roadside diner across from a gas station staffed by two business partners and a couple of grease monkeys.

Except for one early cast change, the musical has stayed intact with the same six actor-singers during 10 runs, starting at Civic Theatre (then at the Indianapolis Museum of Art) and ending at Civic’s current home at Marian University. The cast will perform a 20th anniversary farewell engagement next week.

Along with director Michael J. Lasley, four of the players — Marni Lemons, Karen Frye, Joe Traynor and Reid Miller — sat down at lunchtime recently to talk about the durability of the show. (The other two are Kevin Friedly and Dave Newman.)

When originally cast by the late Bill Hall, they could not have guessed they’d be together after two decades. But the consensus today is that they clicked at rehearsal from the start, and by the end of the first run realized they had been part of something unique. “We’ve enjoyed it so much,” said Traynor. “And it’s fun to be bringing it back to Civic.”

“Pump Boys and Dinettes” was created by a group of New York entertainers in the early 1980s. “It’s the consummate ensemble piece,” said Lemons. “Everybody gets time to shine.”

Though 2007 was the last time this cast performed the show (at Oaklandon Civic Theatre), everything fell into place at rehearsals for the farewell engagement. “It was almost like we’d never stopped,” said Traynor.

“We always liked it because none of the characters was a big stretch for us,” said Miller. “It was like us getting together being us.”

If it’s been so much fun, why not keep it going indefinitely? " ‘Cause we’re old," said Lasley.

“There would have come a time when one of us wouldn’t be able to do the show,” Miller said. “We marked time in our lives by this show.”

“That will be the hardest thing about this,” added Lasley. “It’s the last marker.”