Bert is a blue tender engine who works on the Arlesdale Railway.
Bert was brought to Sodor from England with Rex and Mike for ballast traffic. When the Rev. Wilbert Awdry and the Rev. Teddy Boston accidentally splashed Bert with rainwater, Bert was very cross, and got revenge on the latter by causing him to be soaked by wet tree leaves. He later apologized, and the two clergymen cleaned him, and the Rev. Awdry promised to write about him and the others in his book. Bert was rebuilt in 1973.