Raising Steam by Terry Pratchett

Dick Simnel, a man who knows exactly how a slide-rule works, has invented the steam engine. Suddenly Ankh-Morpork is at the centre of a transport revolution, as journeys across the Sto Plains that took weeks can now be accomplished in hours. The Patrician assigns the semi-fully-redoubtable Moist von Lipwig, late of the Ankh-Morpork Post Office, Bank and Mint, to oversee the expansion of the rail…