Proteus is a legendary narrow-gauge tank engine with a magic lamp hung upon his funnel. Legend has it that should someone find the lamp, their wishes will be granted. Skarloey told this story to the others, which made Peter Sam search the line looking for the magic lamp.
The clues to finding his magic lamp are feeling a rush of wind when the lamp is near, hearing a strange creaking sound, and see a flickering light that shines on and off.
- Proteus made his first appearance in The Cutie Mark Crusaders and the Magic Narrow Gauge Engine.
- Proteus is best friends with Daring Do.