Warning: wikipedia contains spoilers
The story concerns a family who move from London to a rural area after the father is falsely accused of fraud and imprisoned. The three children, two girls and a boy, find amusement in watching the trains on the nearby railway line and waving to the passengers. They become friendly with Perks, the station porter, and with an elderly gentleman who regularly takes the train. He is eventually able to help prove their father's innocence, and the family is reunited.
After a successful BBC dramatisation of the 1960s, the film rights were bought by Lionel Jeffries, and the 1970 film was a great success. The Keighley and Worth Valley Railway and its station at Oakworth were used as location.
The film starred Jenny Agutter and Bernard Cribbins.