4.50 From Paddington

4.50 from Paddington was the train, by which Mrs. McGillicddy was returning home from london.She saw from her carriage window a woman was being srtagled amurdered in the train running parallel to her's. She had reported the phenomenon to the station master of Brackhampton station. But nothing was mentioned in the news paper of the next morning and after enquiring at the police station, police informed that no body was found. None believed her story except her friend miss Jane Marple.......

An apparently impossible solution.