Thomas & Friends is a British children's television series which aired from 9 October 1984 to 20 January 2021. Based on The Railway Series books by Wilbert Awdry and his son Christopher, the series was developed for television by Britt Allcroft. The series follows the adventures of Thomas the Tank Engine—an anthropomorphic blue steam locomotive who lives on the fictional Island of Sodor—as well as his various friends. Initially being filmed in live action on model sets, whereas the latter half of its run was produced using CGI, over 500 episodes were produced over the course of 24 series.