Thomas & Friends (originally known as Thomas the Tank Engine & Friends or simply Thomas the Tank Engine; later called Thomas & Friends: Big World! Big Adventures!) is a British children's television series. It was first broadcast on CITV in October 1984. It is based on "The Railway Series" books by the Rev. W. Awdry and his son, Christopher. The main character is Thomas the Tank Engine, a tank engine that is painted blue. The show takes place on the made-up island of Sodor. There are two main railways there. One of them is run by Sir Topham Hatt. The other one is a different size. Thomas runs on the main one (the one that is run by Sir Topham Hatt).