Bertram, nicknamed "Old Warrior" for his bravery, is a courageous and loyal tank engine. He is the main protagonist of Bertram: Old Warrior.
Built at Boston Lodge in 1849, following the hasty departure of his brother Duke, Bertram was informed by Gareth Heilwyn that he unable to be fitted with a tender and was to work on the Cynwrig Railway.
In 1905, Bertram helped prevent a serious accident involving a runaway train that had broken away from his friend, Gwydion. The following day however, the engines were informed by their deputy controller, Huxley Billingsworth, that their controller, Ellis Garth had died. Bertram was then unwillingly sold to Caderyn Gerralt to work on the Alun Railway.
Bertram is a brave and loyal engine with a natural intuition and charisma. An opposer of injustice, Bertram won't hesitate to fight evil.
Bertram is a Boston Lodge 0-4-0ST, modified to be a tank engine.
Bertram is painted dark brown with red lining and has two brown plaques on either side of his saddletank with his name written in gold.
Bertram will appear in all the episodes of the series.