In Billy Wilder’s immortal 1950 comic film noir “Sunset Boulevard,” broke screenwriter Joe Gillis has a blowout while being chased down the eponymous road by men sent to repossess his car. He hides his crippled jalopy in the garage of a decrepit and, so he believes, deserted old mansion. This is how he falls into the employ — and soon, the sick embrace — of the house’s owner, the deranged silent-film star Norma Desmond. So it’s fitting, in a way, that I was involved in a minor car accident on my way to Signature Theatre to see its new staging of Andrew Lloyd Webber’s 1994 musical gloss on the movie, missing the first 15 minutes of the show. I entered just before Norma — here inhabited by Florence Lacey, the last actor to play Eva Peron in “Evita’s” original Broadway run — does. Upon learning Joe (sturdy D.B. Bonds) is a writer, she demands that he doctor the swollen script of a “Salome” remake via which Norma plans a comeback that everyone around her — meaning Joe and her overprotective butler, Max — knows will never materialize.

What’s apparent from the 140 minutes I did see is that this is a first-rate version of the second- or possibly third-rate musical that Webber hath wrung from Wilder’s unimpeachable movie. Signature looks to have spared no expense: Scenic designer Daniel Conway has impressively re-created, in the same space, both Norma’s haunted old eight-bedroom palace and the ropes, lights, and sandbags of a midcentury soundstage. Norma’s 1929 Isotta-Fraschini — the luxury car that contributes a key plot point — is here, too. Even better, director Eric Schaeffer has stuffed a 20-piece orchestra into the intimate, 276-seat confines of Signature’s main house. Conducted by Jon Kalbfleisch, the musicians sound sublime though the songs are, with one or two exceptions, ersatz and maddeningly repetitive even by Webber standards. You resent their intrusion almost every time one limps in to interrupt the story that book writers and, far less successfully, lyricists Don Black and Christopher Hampton have preserved intact from Wilder and Charles Brackett’s screenplay, which remains a harrowing, wickedly funny tale of obsession and compromise in Hollywood.