WASHINGTON — For many theaters, it’s hard enough to pull together the money to produce one new musical, let alone two at the same time.

But the Signature Theater of Arlington, Va., is jump-starting its new season this month with a pair of world-premiere tuners in rotating repertory.

On tap are “The Hollow,” a reinterpretation of Washington Irving’s “Legend of Sleepy Hollow” by Hunter Foster (book) and Matt Conner (music and lyrics), and “The Boy Detective Fails,” an adaptation by writer Joe Meno of his own novel with music and lyrics by Adam Gwon (“Ordinary Days”). Signature believes its eight-week premiere-in-rep concept may be a first.

Even though the two productions share the same design team, orchestra and ensembles, the pairing isn’t going to save Signature any money. Economies will be offset by lengthier rehearsals, modest salary increases and lots of overtime, according to general manager Maggie Boland.

Rather, she says, the event is intended to emphasize Signature’s mission to develop new musicals in a competitive theater town that encompasses an array of orgs, including Arena Stage, Studio Theater, Woolly Mammoth and the Kennedy Center.

“Hollow” and “Boy Detective” are the latest under Signature’s 5-year-old American Musical Voices project, supported by Ted and Mary Jo Shen. The Shen Family Foundation has contributed more than $780,000 in direct support of artists including Michael John LaChiusa (“Giant”), Ricky Ian Gordon (“Sycamore Trees”) and Joseph Thalken (“And the Curtain Rises”).

A second phase of the program, dubbed the Next Generation, was launched in 2008 to support emerging composers, including Conner, Gwon and Gabriel Kahane. In all, nine commissions are in Signature’s Shen-supported pipeline, although full productions are not guaranteed.

The first tuner under the Voices program to travel after its Signature gestation was LaChiusa’s “Giant.” The production received a staged reading at Gotham’s Public Theater in January, and is slated for a January mounting at the Dallas Theater Center. Roughly an hour will be chopped from the four-hour epic that bowed at Signature to mixed reviews.

The rep series is a challenge that Signature a.d. Eric Schaeffer says is important to the future of the American musical. He had initially planned to stage “Hollow” himself until another directorial obligation intervened — the Kennedy Center’s production of “Follies,” which opened Sept. 12 at Broadway’s Marquis Theater (see review, page 73).

Instead, “Hollow” is staged by Signature Theater associate a.d. Matthew Gardiner; it features Sam Ludwig and Whitney Bashor. “Detective,” directed by Joe Calarco, stars Stephen Gregory Smith and Anika Larsen.

The Signature crew hopes the increased attention generated by the unique programming gambit will make the extra effort worth it. “Cost-savings were definitely not the motivation for this,” Boland says.