@AnimuVsMango I think it's not either particular way. The author was just like "I had this idea, so I want to draw it." Some of the human characters later on may also be loosely based on existing characters.
Being a train conductor myself, it's a classic... One person complaining that it's hot and another one saying that he's freezing in the same d*mn coach. Usually the solution is telling the first one you're giong to lower the temperature, and the second one you're going to raise it. The placebo effect does the rest