Ankh-Morpork, the largest city in the Discworld, has always been a true cauldron of activity—elsewhere, life was rather tranquil. But now the steam locomotive is making its way onto the Disc. Lord Vetinari quickly decides to harness the iron beast. He appoints Moist von Lipwig—Master of the Post, the Royal Mint, and the Royal Bank—to also get the transportation system rolling. Soon, construction on the railway network is bustling everywhere. However, not everyone appreciates the rolling progress. A radically conservative splinter group of dwarfs takes advantage of the steam engine to put significant pressure on the ruling class.