Can you tell us more about Proteus's relation with other ghost engine plz (◕ᴗ◕✿)
Im gonna assume you mean the triangle head guy, whos name is Hexham!
Hexham, unlike Proteus, is not from Sodor. Hes from a completely different time only being able to travel back because the concept of time is nonexistent to him. Engines in his era are nuclear powered and thus need to be large to accomodate that power source. When he saw Proteus, another ghost who he can interact with, he was metaphorically scratching his head. Why are you so small. Teeny tiney.
Proteus was the same, but it was because Hexham is a fricking giant.
I imagine them as very close friends, once they got to know eachother. Their conversations are full of banter where they call eachother names and insults, but its all in good fun. Hexham calls Proteus a moldy banana peel. Proteus calls Hexham a fat rustbucket. They both laugh it off afterwards.
Within their little ghost clique of 4, Hexham and Proteus are the only ones who talk to eachother. Literally. The Weld is selective mute due to their circumstances and Jacana communicates by growls and snarls. Proteus had spent most of his afterlife utterly alone, no alive engine ever able to see or hear him. Hexham needed company from someone who understands his undead situation. It was only natural for them to cross paths and develop a bond, especially since Hexham cant talk about everything with Edward.
They talk a lot about Edward. They talk a lot about Skarloey and Rheneas. They talk a lot about their previous lives and how much everything changed since they became spectres.