Bertram, nicknamed "The Old Warrior" for his bravery, is a small tender engine who was found by Toby. Toby thought Bertram was a ghost after hearing a story by Thomas. He now works at the restored mines, taking passengers to the fairground within.
Bertram is a Small England tender engine, like Duke. Several of his class can be seen working on the Ffestiniog Railway.
- It is currently unknown when Bertram will appear in the series.
- According to Britt Allcroft, Bertram was supposed to be a tank engine, but financial difficulty in building a new model made them repaint Duke's model with Smudger's face.