There's potentially a great thriller to be found in the content of The Girl on the Train. In fact, there already have been. A witness to a potential crime who isn't sure exactly what she saw, men using domestic authority to trick the women they love into doubting their own handle on the truth, someone who isn't confident that they didn't commit a crime in the period that they've inconveniently lost to a memory black-out, and a person who willfully misrepresents her identity to have access to a world she dreams about but could never be part of on her own: you don't even have to leave the filmography of Alfred Hitchcock to find a film on some iteration of every one of those subjects. Or you can just park yourself in the first half of the 1940s and find them all there, and then you get to add in the fact that The Girl on the Train is also a dipsomania picture, and add The Lost Weekend to the pile, and you're all set.

A lack of originality is hardly the film's problem. Being a bad movie is. I cannot swear to the reason why, exactly, The Girl on the Train doesn't work. The script, adapted by Erin Cressida Wilson from Paula Hawkins's celebrated 2015 novel, has enough of the crackling energy of a twisty whodunnit that it falls into a kind of grabby magnetism just by default. It's certainly not boring, that is to say. The idea behind the film is that Rachel Watson (Emily Blunt), a low-functioning alcoholic, passes by the tony Hudson Valley neighborhood where she used to live with her ex-husband Tom (Justin Theroux), as she commutes into Manhattan on the train. Here, she tries very hard not to spy on Tom and his new wife, Anna Boyd (Rebecca Ferguson), instead preferring to gawk at their sexy neighbors, the Hipwells, Megan (Haley Bennett) - who's also Tom and Anna's nanny - and Scott (Luke Evans). And oh, how this life as a shabby voyeur does please her and give her something of an imaginative inner life, up until Megan goes missing, presumed dead, right after Rachel has come out of a particularly bad bender, with nothing but a few fragmentary memories that might point to her having murdered the pretty young thing.

The film makes a feeble attempt at being Rachel's story and Anna's and Megan's, revealing the Hipwells' marriage to be founded on emotional abuse and the ravings of two very unpleasant human beings who have no clear reason to still be together long before Rachel notices Megan kissing a strange man, and resolving to confront the younger woman as a tawdry harlot. But it doesn't take: firstly, because Anna's plot doesn't even start to have a conflict until about two-thirds of the way through the movie; secondly, because Megan's plot takes the form of time-stamped flashbacks which are downright proud to announce how much they're not trying to fit in with the rest of the movie in a structurally organic or thematically resonant way; thirdly, because Ferguson and Bennett both suck. Actors sucking is no rarity in The Girl on the Train: Evans, playing a thuggish bully, deliberately eschews the brooding hunk charisma that's the one and only card he has to play as an actor, while Theroux is nothing but wallpaper, failing entirely to set up the secrets we learn about his character as the movie progresses, and never emerging as more than White Dude with Cleft Chin #287. By virtue of being inherently better actors, ร‰dgar Ramรญrez and Allison Janney are sort of automatically more worth paying attention to than most of the cast, but their roles - lothario psychiatrist and unreasonably smarmy police detective, respectively - are very tiny, and so bluntly functional that they barely rise to the level of "thankless". But Ferguson and Bennett are both special kinds of awful even within the context of this cast.

That leaves it entirely to Blunt to be the human focal point of the movie, and she sure as hell does go for it: granted a whole cluster of everyone's favorite showstopping traits (alcoholism, sexual jealousy, sexual ardor, a soul-searching psychotherapy session, plate-flinging, gazing at a baby), Blunt dials everything up as far as it will go and plays the character with the virtuosity of a great violinist tearing through the Four Seasons. It is not, maybe, the most intellectually stimulating use of her talents, but by God, it does get the heart pumping. If the trashy melodrama that makes up the film ever comes to life, it's thanks exclusively to Blunt pouring everything she's got into the haggard expressions, slurred dialogue, animalistic moans, and hungry stares that animate her character.

It's certainly not anything done by Tate Taylor, a director who makes embalmed middlebrow mediocrity like it's his job (which, when you get down to it, it probably is: you don't hire the guy from The Help because you want a better movie than The Help, I guess), and who is I suspect responsible for the worst things about The Girl on the Train: its sluggish qualities, exacerbated badly by the momentum-crushing flashbacks to Megan's story, and its simultaneously predictable and muddled thriller plot. The film deploys red herrings so noisily that it quickly becomes obvious who the least-obvious possibility for the killer is, and figure that this is the kind of movie that's going to go that direction, but the actual expression of motivations and feelings among the characters is almost impossible to parse on a scene-by-scene level. Anna especially, who really only has the inner life necessary to justify inane plot points.

Besides which, it really is quite a tacky splat of exploitation. In principle, the film is exploring multiple different social messages about the World of Today: the crippling power of alcoholism, and the violent potential of the overprivileged man, mostly. In practice, these things are so obviously set dressing that it rather reflects poorly on the film than well, that it wants to steal some sense of gravitas from indicating these themes without in any meaningful sense absorbing them into its soul. The alcoholism plot is especially galling: the notion, I think, is that we're meant to read this as a stirring tale of how Rachel rebuilds from the ashy ruins of her vanished life, struggling to assert her dominance over all her demons. And that's basically how Blunt plays it, albeit histrionically. The tone of the movie, though, is like watching a particularly sudsy Susan Hayward vehicle, gawking at its lead actor with the bravura of a carnival barker hustling us to come see the gorgeous Emily Blunt play a sweat-slicked, burned-out wino. The crassness I could handle; the crassness wearing its very posh, Tate Taylory sense of being oh beg pardon, a very classy prestige picture, adapted from quite the literary sensation, you know โ€“ that I cannot stomach for even a second. Barely more than functional as a thriller and a star vehicle at best, I can only describe The Girl on the Train as trash: not the fun, feisty kind of trash (like, for example, Susan Hayward vehicles), but the kind that you wad up into a ball and toss into a bin and forget about an instant later.