NEW YORK — Producers and creatives of the upcoming Broadway revival of Tennessee Williams’ “A Streetcar Named Desire” can get a glimpse of the way the legendary original production came together, thanks to a recently unearthed sheaf of notes taken during the pre-Broadway run of “Streetcar” in New Haven in 1947.

The documents, which include performance tweaks, script questions, tech notes and a complete copy of the revised rehearsal draft, was unearthed by Mary Boehlert Katz, who at the time had been dispatched by her employer, producer Irene Selznick, to assist helmer Elia Kazan during the Connecticut run-up to the Rialto.

Katz, whose daughter is much-employed lighting designer Natasha Katz, briefly considered throwing away the stack of old notes, but ended up donating them to the New York Public Library for the Performing Arts, where scholars and other legiters can take a look at a wider collection of “Streetcar” papers that includes extensive documentation of the original set designs by Jo Mielziner.

“What’s most interesting in the new materials is the picture of how detailed Kazan was in his directing,” says Karen Nickeson, curator of the library’s Billy Rose Theater Division. “He corrected every gesture, the tone of voice, the timing.”

Flipping through the pages reveals scene-by-scene staging tweaks, including, “Blanche pat Stanley tummy to pacify him,” and “Stella smooth out bed more.” There don’t seem to have been many changes made to the script itself, although at one point Kazan wondered, “TENNESSEE: Don’t you think speech of Blanche’s too long about deaths at Belle Reve.”

Also among Katz’s papers were notes written by Hume Cronyn to Kazan regarding the developing performance of his wife, Jessica Tandy, who originated the role of unstable Southern belle Blanche DuBois. (No word on how Tandy felt about the spousal critique.)

Such minutiae always prove useful to scholars, and can also come in handy for revival producers, who must contend with the lingering ghost of an original production that starred Tandy, Marlon Brando, Kim Hunter and Karl Malden.

The upcoming revival, for instance, aims to take the original into account while opening up the racial mix of the cast, with an ensemble led by Blair Underwood, Nicole Ari Parker, Daphne Rubin-Vega and Wood Harris.

“We’re trying to stay true to the script, but make the cast more of the racial gumbo of New Orleans,” says producer Stephen Byrd, also behind the all-black revival of Williams’ “Cat on a Hot Tin Roof.” “We want to bring the balance back to the play. It often becomes the Blanche show, but we want you to remember each and every character.”

Discovering the “Streetcar” papers, misfiled in an old metal cabinet, brought back fond memories, Katz says. “None of us realized the play was going to be what it was,” she says.

It went on, of course, to become a landmark in American drama, produced regularly all over the world. But Katz hasn’t seen too many other stagings of the show.

“Nobody will ever replace that first cast, as far as I’m concerned,” she says.