The gaslight of the film [The Girl On The Train] became something that really needed to be dramatized more than the book did, because it wasn't going to read as strongly on screen.

It's what you do when you have Allison Janney.My jaw-dropped at her performance. You think that part is sort of a regular part until she steps into the shoes of the officer. She just filled it with such dimension and by giving her the whole shebang, the whole police thread, I think it was the right choice.

I really wanted Rachel [from the Girl on The Train] to be purely fixated on fantasy and on her ex-husband.I didn't want her to be embarking on romance, touching people I wanted her purely in the realm of fantasy and frustration and dreaming and sadness.

Just because Rachel [from the Girl On The Train] is an unreliable character doesn't mean she has sex with anybody who walks by her. It was important to keep her a little virginal.