Well, the people with red eyes are all from a particular group that everyone considers horrible and barbaric savages. They're pretty much just prejudiced, it ain't gotta make much sense as to why.
the carriages uses leaf springs thats better than an axle straight up
everyday i read these kind of manga/manhua i cant stop thinking how do they ride. is it like painful ride or a smooth ride. I stayed up all night thinking what would be the cart suspension would be.