I Still do NOT think that "Gus the Snake-Bus" that Charles is afraid of is a reference to THIS;
After all; THIS Snake isn't wearing a Bus as a Protective outer shell like how Charles wears a Train as a Protective Armor; since Mankind has developed weapons that are more deadly to them; than the Bows & Spears they faced against tens of thousands of years ago according to a Stone Tablet found for a Sidequest from Choo-Choo Charles