APPARENTLY, six decades of coast-to-coast TV morning network news inspired academic Paula Hawkins to write a novel that, in turn, inspired Erin Cressida Wilson to write a screenplay, which gave director Tate Taylor the inspiration to make this mix of chick-lit and forensic mystery.

Being a train freak for whom the inability of engineers to build an ocean-crossing railway is cause for some disappointment, I hoped to see a film of mystery on board a commuter train in upstate New York. But exteriors showing trains mostly appeared as CG images running along a permanent way on which I counted an odd number of rails. I found that hard to accept. The title should correctly be “The Girl From the Train” carrying Rachel (Emily Blunt) past a semi-rural suburban house and one day seeing a man enthusiastically embracing Megan (Hayley Bennett) on the balcony.

Rachel has no difficulty in recognising him. He’s Tom (Justin Theroux), from whom she has been divorced long enough for him to marry Anna (Rebecca Ferguson) and beget in her the child whom Rachel had never had and whom Megan is in fact nannying.

What’s going on? Within the small network of spousal confusions basically arising out of Rachel’s unstable behaviour, quite a lot. She dominates a mystery that includes Anna and Megan whose physical similarity is pivotal to the story, close friend Martha (Lisa Kudrow) and police detective Riley (Allison Janney), together guiding us along pathways tangled by her employment history, her drinking habits and her mental instability.

Who really dunnit? Who really had it done to her? Why did it get done? By about minute 106 of the film’s 112, the answers have become less a relief of tensions than an explanation of the inexplicable. At least, that’s how it seemed to this mere male.

At all cinemas