Harrowbarrow could not directly dig through rock, so it drove through other cities' filled-in tracks. It was once a scavenger town until it was captured by a hunting city in the Frost Barrens. Instead of digesting it, they though it might be useful for the Green Storm War, so they took it it to Murnau whole, and the mayor let his son Wolf take command of it. It is technically a suburb of Murnau, although it does not seem particularly loyal to the city.
It ate fellow towns despite the treaty, and was extremely unethical. When Wolf found out about New London, he attempted to destroy it and use its technology to make Harrowbarrow a flying city. Harrowbarrow was destroyed when General Naga flew a Green Storm airship into it's mouth, blowing it up.