The book has bumped corners. (see photo)

A new invention arrives in Ankh-Morpork - a massive, metallic, rumbling monster that has harnessed the power of all four elements: earth, air, fire, and water. Steam begins to rise over the Discworld, created by the locomotive of Mr. Simnel, a man in a peaked cap armed with a slide rule. Mr. Simnel has an interesting arrangement with sines and cosines, and thanks to them, he controls the Iron Girder - the first Discworld locomotive. Moist von Lipwig isn't the type of person who loves hard work.

However, in his roles as Postmaster General, head of the Royal Mint, and the Royal Bank of Ankh-Morpork, his dedication is vital; though it consists mostly of words, which fortunately aren't heavy and don't need oiling every five minutes. Moist is a lover of life, which is why he can't refuse the new job offered to him by the Patrician.

Moist will have to deal with gallons of axle grease, goblins, a fat businessman rumored to throw employees down the stairs, a number of furious orthodox dwarf-engineers, and many other obstacles if he doesn't want everything to go off the rails…