Killer engines

The fantasy novel, set in the distant future, revolves around the struggle of cities that survived a brutal war called the "Sixty Minute War" to remain on the now desolate and barren land. The surviving cities use giant wheels to move around and attack and prey on smaller cities in an effort to replenish their resources and survive.
A young girl named Hester appears, seeking revenge on the killer of her parents, who belongs to London, the great moving city, and fate throws a young man named Tom into her path.