Bertram is the old warrior engine in Thomas the Tank Engine and Friends. The other engines initially thought he was a ghost who haunted the mine that was discovered by Toby the Tram Engine & Sir Topham Hatt's family. After being found, he was restored to working order, & now he has been seen working in the old mines, which have now been turned into a tourist attraction.
Bertram used to work in the mines with the other "little engines" in a remote part of Sodor. His fate was unknown to many after the mine's closure, and it was assumed he was left to rust. He remained at the mine until it was rediscovered years later.
Not much is known about his personality, but it is said that he is very brave.
Bertram is based off of Prince, a 0-4-0 saddletank tender engine from the Ffestiniog Railway at Porthmadog, North Wales, Duke is another member of this class.
- Bertram on the Thomas the Tank Engine Wiki