Marklin is a black tank engine like Rosie but bigger than her. From Season 13-onwards, he has a face (same as Henry's). He is voiced by Kerry Shale in UK and Michael Brandon in US.
Marklin's model was modified for Puffa in the sister show, TUGS. He was painted gray and was given an American-style whistle, an oil-burning headlight, a diamond smokestack, and a cowcatcher