Bertram, nicknamed "the Old Warrior" for his bravery, is an old narrow gauge engine who worked in a quarry on the far side of Sodor.
Bertram used to work in a series of mines with other "little engines". His fate was unknown to many after the mine's closure, and it was assumed he was left to rust. However, Toby found him whilst watching over the quarry one night, and has since befriended him. He now works at the restored mines, taking passengers to the fairground within. But after his selfish accident in 1900, he then joined the Skarloey Railway forever and ever.
Nothing is known about Bertram's persona, other than that he is considered incredibly brave.
Bertram is painted maroon with red lining.
- According to Britt Allcroft, Bertram was supposed to be a tank engine, but the model crew made a mistake.