This challenge is a tough one. I had various ideas including a literal landship. In the end I have gone for something insectoid and non-fantasy. If I'm going outside my comfort zone then I may as well go all the way.
Anyway I have decided to make a sketch of it before I map it. It doesn't actually have a name it - is just based on the shape of a giant african milipede.
...I have no idea how I'm going to map it though.