I thought the concept behind the book was ambitious, perhaps more so than in other Discworld books. Pratchett wanted to show a complete process of historical change due to technology, and its consequences, across a whole continent. He takes us from the invention of the steam locomotive to the creation of railway companies, cultural change resulting from the railways and the political consequences of being able to move things and people around at great speed. The thing is, it’s just a bit too much for a book of this size, and he didn’t quite pull it off. Plot, character development, and that special set of very human values Pratchett usually infuses into his books all suffered a bit. It was still fun to read, but not my favorite Discworld, by any means.