Dunbar has a strong work ethic and acts as a mentor for the younger engines. When an engine has low confidence, Dunbar encourages them to keep on trying. He is full of helpful tips and advice and takes pride in his position of shunter, making sure every engine gets the right rolling stock for each train.
Dunbar is based on a hybrid cross of a Union Pacific EMD GP38-2 diesel engine and a Vietnam Railways D12E.
Dunbar is painted olive green with dark green sidings, cab roof, and underbite. His handrails are also bronze.
- Milan Prsa, the creator of the series, stated that one of his dominating facial features, his underbite that vaguely resembles a cowcatcher, may be redesigned in the series. According to Milan's second Twitter account, Milan stated that he does not like the design because of how uncanny it looks.