**1/2. After an Agatha Christie premise, Deanna-Marple-Durbin, helped by a writer of crime stories, investigates a murder. I'm not very fond of the comic film noir genre but there are a few oddities in Lady on a Train. Firstly, the quasi-incestuous relation between Ralph Bellamy and his aunt Charlotte then the attendance by phone of H.G. who seems less a father to Deanna than her pimp sending her to his NYC branch.