Bertram, also known as "The Old Warrior", presumably because of his bravery, is a narrow-gauge engine.
He is sometimes called Bertrum.
That's about it, really.
While on guard duty at a recently rediscovered mine, Toby met Bertram on a siding, mistaking him for a ghost. He soon befriended Toby however, and was restored to his former glory. The mine was turned into a tourist attraction, where Bertram now ferries passengers.
- ERTL (2000)
ERTL Bertram is a repaint and slight retooling of ERTL Duke. On this version of the engine is a nameplate that reads "Bertrum."
The prototype of the toy had Duke's face.
- Wooden Railway (2000-2003, 2012, 2016)
The first incarnation of Bertram in Wooden Railway form was released in 2000, exclusive to a pack with two "scrap cars", in differing shades of blue. Here, he is a tank engine, who is predominantly coloured chocolate brown and red. This version was discontinued in 2003.
Wooden Bertram made a comeback in 2012, albeit without his scrap cars. This release is virtually indistinguishable from the original release.
In 2016, Bertram finally got a redone wooden toy, receiving a slightly modified paint job and, at long last, a tender! That being said, he still retains the "tank engine" shape, leaving the final product looking like a tank engine with a box tacked at the end.
- Trackmaster (2009)
Surprisingly not a retooling of Duke, Trackmaster Bertram is a stubby, battery-powered version of the character. As with the ERTL toy, this incarnation has a livery of brown with red stripes, and once again carries the nameplate of "Bertrum." However, the box of the toy actually spells his name correctly. Sometimes.
- According to Britt Allcroft, Bertram was actually supposed to be a tank engine. However, as the company then could not afford the construction of a brand new model, let alone one that would only be used for one episode, the model of Duke was repurposed, and given the face of another one-time character, Smudger.
- As he is a repurposed Duke, Bertram can also be considered based on the locomotive "Prince" stationed in the Ffestiniog Railway.