The Girl on the Train at the Alhambra

RACHEL Watson’s life is a mess. A barely functioning alcoholic, she lives alone in a grubby flat, surrounded by empties, and wakes up with cuts, bruises and no memory of the night before.

Lonely and bitter following her marriage break-up, she seeks escapism in a seemingly perfect couple she spies from the train on her daily commute. But when the woman she’s been secretly watching suddenly goes missing, Rachel finds herself at the centre of a mystery that relies on her piecing together events blurred by her drinking.

Based on Paula Hawkins’ bestselling novel, The Girl On The Train is a compelling stage thriller. While the film took the story to a New York suburb, the play returns to the unremarkable London commute that sets the scene in the book.

It works well on stage, thanks to James Cotterill’s atmospheric set - you can almost smell the stale booze in Rachel’s poky flat - and Ben and Max Ringham’s unsettling score. The train is an effective illusion, thanks to innovative staging, sound and lighting, and there's a lingering sense of social isolation and discontent.

Rachel is a complex heroine - when we first meet her she's swigging from a wine bottle and throwing up into a pizza box. Her memory is hazy, but it appears she has been harassing her ex-husband's wife. That we care for Rachel, and come to trust her shaky version of events, is to Samantha Womack's great credit. Womack plays Rachel as a believable drunk - trying to hold it together, slurring just enough, not too wobbly, clutching a water bottle half-filled with vodka - and it's a subtle, nuanced performance that strips away at her psyche. Rachel is guarded and bitter, but as she slowly unravels we're rooting for her.

As the action twists and turns, our allegiances shift between the two couples linked by the young woman's disappearance. Is Scott, beautifully played by Oliver Farnworth, capable of killing his wife? Is Rachel's ex, Tom, as caring and capable as he seems? Adam Jackson-Smith is excellent as Tom, as is John Dougall as jaded DI Gaskill.

And what of the missing Megan, who is flawed and unfaithful but hides a dark secret that only her therapist (charismatic Naeem Hayat) knows about? Kirsty Oswald brings an endearing vulnerability to Megan, whose past unfolds in moving monologues, and Tom's wife Anna is rounded and likeable, thanks to Lowenna Melrose.

The plot twists seem a bit condensed for the stage, and the final scenes lack the emotional punch of the film, but this is nonetheless a gripping psychological thriller exposing some uncomfortable truths about urban life.

Runs until Saturday.