Rent Miss Marple: 4.50 from Paddington (2004)

Mrs McGillicuddy is woken from a very pleasant dream by a train suddenly pulling parallel to hers. As they draw level, a blind flies up and she finds herself staring straight into the eyes of a woman being throttled by a man, who is silhouetted against the window. As the woman’s life ebbs away, the train speeds up, leaving Mrs McGillicuddy staring into the darkness and wondering if she is having delusions.