Before working as a model maker for Thomas, Christopher designed and made several props for animated television commercials like "KC Nuts" and "Prize Guy Yoghuts". In 1982, he and David Mitton worked together on making the advert of "Ever-Ready Battery". During the production for the first season of Thomas, Christopher made several models like the schoolboy on a bicycle (which was seen during the opening credits), drivers, guards, Jeremiah Jobling, and Sir Topham Hatt, as well as Maron station, Lower Suddery, Henry's Tunnel, Tidmouth Sheds, and The Viaduct.