'Arry and Bert

'Arry and Bert are two diesel twins who first appeared in the fifth season episode "Stepney Gets Lost", discovering Stepney, abandoned, in the scrapyard after his crew went for help. After crowing their victory against the steam engines, they pushing him into the scrapping sheds. Luckily for Stepney, the Fat Controller had chosen that night to tour the scrapyards, and saved Stepney just in the nick of time.

They enjoy playing tricks on the engines, such as making the others "middle engines". Like Diesel, they are "enemy" characters.

Trivia

 * 'Arry and Bert were two of the first characters to only appear in the television series.
 * 'Arry and Bert's models were originally used for Splatter and Dodge in "Thomas and the Magic Railroad".