Lady on a Train (1945)
While watching from her train window, Nikki Collins witnesses a murder in a nearby building. When she alerts the police, they think she has read one too many mystery novels. She then enlists a popular mystery writer to help her solve the crime on her own, but her sleuthing attracts the attentions of suitors and killers. film noir, murder, inheritance, train, witness to murder, heiress, madcap comedy, crime fiction writer, mystery
ETC.
