Thomas & Friends (originally known as Thomas the Tank Engine & Friends and later Thomas & Friends: Big World! Big Adventures!) is a British children's television series that aired across 24 series from 1984 to 2021. Based on The Railway Series books by Rev. W. Awdry and his son Christopher, the series was developed for television by Britt Allcroft. The series follows the adventures of Thomas, an anthropomorphised blue steam locomotive on the fictional North Western Railway on the Island of Sodor, and many other anthropomorphised locomotives on the North Western Railway, including Edward, Henry, Gordon, James, Percy, and Toby. They work for Sir Topham Hatt, primarily known as the "Fat Controller".