The Railway Children (2000)

The Railway Children is a 2000 British drama television film based on the novel by E. Nesbit.
Genre:Family

Jenny Agutter (who played Bobbie in a 1970 film version) stars as Mother alongside Sir Richard Attenborough in a Masterpiece Theater television presentation of Edith Nesbit's popular novel. Set in Yorkshire at the dawn of the 20th century, The Railway Children is the story of three children whose father has been wrongfully imprisoned for espionage, though they know nothing of this; their mother refuses to tell them why the police took away their father. The children spend their free time exploring the mystery of their father's disappearance and gazing at the nearby railroad, in the hope that it will somehow bring them an answer. After they help prevent an accident on the railroad, the children are befriended by a mysterious old gentleman (Attenborough), who may be able to provide some answers.

http://www.imdb.com/title/tt0215111/
http://en.wikipedia.org/wiki/The_Railway_Children_(TV_film)