The curse of high expectations dogs many films made from popular bestsellers, and it afflicts this adaptation of Paula Hawkins’ 2015 smash, s multi-perspective, quasi-feminist thriller that undoubtedly worked better on the page than it does on the screen. That isn’t to say that Tate Taylor’s adaptation, made from a screenplay by Erin Cressida Wilson, isn’t sporadically effective, largely because of a strong lead performance; but by the time the big revelation-confrontation rolls around, it’s descended to a potboiler level that is easier to swallow when reading than it is when watching. The finale is so over-the-top that it might remind you of the ludicrous conclusions that regularly bedeviled those suspense teleflicks that were a regular part of the ABC schedule back in the seventies. (Steven Spielberg’s “Duel” was one of them, but it was obviously miles ahead of the others, no pun intended.)

The title character is Rachel Watson (Emily Blunt), who rides the commuter line from Ardsley to Manhattan daily (the locale is altered from London)—not because she needs to get to a job (she was fired on grounds of alcoholism some time ago) but as a ruse to convince Cathy (Laura Prepon), the girlfriend she’s been crashing with “for a few weeks” that she’s still employed. The route also goes past the house she used to live in with her ex-husband Tom (Justin Theroux), who now occupies it with his new wife Anna (Rebecca Ferguson) and their infant daughter, and since Rachel’s still obsessed with him, she wants to spy on them as often as possible.

But while Rachel’s en route to the city, where she’ll spend the day walking about or sitting with a sketchpad at Grand Central and constantly sipping from the water bottle she’s filled with vodka, she also becomes interested in a house down the block from Tom’s, where a lovely blonde, whom we learn is named Megan Hipwell (Haley Bennett), is enjoying an apparently idyllic marriage to burly, handsome Scott (Luke Evans). Rachel’s fantasy of theirs as a perfect union is shattered, however, when one day she sees Megan on her balcony, hugging a man other than Scott, and presumes an affair between them, though the stranger will turn out to be Megan’s therapist, Dr. Abdic (Edgar Ramirez). Another point of which Rachel is unaware is that Megan has been acting as nanny to Tom and Anna’s child.

Wilson and Taylor dole out all this information in a fractured narrative that not only shifts from woman to woman—the men all remain decisively secondary characters—but also jumps around temporally, often taking us into the past in what amount to flashbacks. Many important moments are shown more than once from the perspectives of different characters, so that the viewer is called upon to piece them together as the jagged shards of story are introduced. The intention is obviously to force us into a state of mind not unlike Rachel’s, in which her habitual tipsiness leads to blackouts and memory loss.

That’s a central element when the thriller plot kicks in. Rachel gets off the train one evening in order to accost Megan, and awakens later in her bed, covered in blood and mud, unaware of what happened. Later Megan turns up missing, and Rachel will be questioned by a police detective (Allison Janney) interested in what she might have seen. Did Rachel have a hand in Megan’s disappearance? Or did Scott, who turns out to be a volatile fellow, whom Rachel approaches to tell him of Megan’s apparent infidelity? Or was the doctor implicated, or perhaps the strange man (Darren Goldstein) who stares at Rachel all the time on the train, and followed her when she was chasing down Megan?

The problem with all this is that the effort to generate suspense by providing a battery of suspects proves unsuccessful. The identity of the person responsible for Megan’s fate will be fairly obvious early on to most viewers—so much so, in fact, that you wind up hoping you’re wrong and that the script will pull an unexpected rabbit out of the hat. But it doesn’t. Another difficulty is one that accentuates the difference between the effects of novel and film. Simply put, some of the flashbacks are deceptive, showing things that didn’t happen. A novelist can get away with this sort of misdirection by couching the memories in terms that allow for their unreliability. When shown on film, on the other hand, they take on an aura of reality that’s hard to slough off later, and as a result they come off feeling like cheats. And they’re a central element in the mystery at the heart of the movie.

Still, though the premise of a mentally fragile protagonist who might be a murderer is an old pulp standby (check out, for instance, the 1947 film noir “Fall Guy,” based on a Cornell Woolrich story, among others), Blunt brings an authentic feeling of dissipation and desperation to Rachel. Her performance, however, is the single outstanding one among the cast; all the others do what is asked of them, but they’re really nothing more than necessary cogs in Hawkins’ slick but emotionally superficial plot. Similarly, most of the behind-the-camera contributions—Charlotte Bruus Christensen’s cinematography, Michael McCusker’s editing, Kevin Thompson’s production design—are thoroughly professional but not outstanding. Danny Elfman’s score—a brooding assemblage of what sound like electronic groans and grunts, totally unlike his usual work—is, however, exceptionally atmospheric.

“The Girl on the Train” might be a great read, but despite Blunt’s virtuoso turn it’s only a so-so movie.