The story concerns the Waterbury family who move to "Three Chimneys" a house near the railway after the father who works at the Foreign office is imprisoned as a result of being falsely accused of selling state secrets to the Russians. The three children Roberta (Bobbie) Peter and Phyllis find amusement in watching the trains on the nearby railway line and waving to the passengers. They become friendly with Albert Perks the station porter and with the Old Gentleman who regularly takes the 9:15 down train. He is eventually able to help prove their father's innocence and the family is reunited.The family also take care of the Russian exile Mr Szczepanskywho came to England looking for his family (later located) and Jim the grandson of the Old Gentlemanwho suffers a broken leg in a tunnel.