Get Your Screwball On: The Girl in the Train by Agatha Christie

That's right, there's no typo in this episode's title: it's The
Girl *IN* the Train, and we wouldn't have it any other way. Well,
perhaps we would have a meatier mystery and more three-dimensional
characters, but we couldn't help enjoying this simplistic and
somewhat fantastical early thriller story.... Think of it as
Christie on a busman's holiday, enjoying herself the entire way.