Pratchett condenses the development and spread of steam trains into a single novel. And because he does this, it's not just a love song to trains and trainspotting, but also a social history that includes banditry, and terrorism, and social improvements like housing and food safety improvements as well as great strides forward for suppressed native peoples and women, also finance. Everything really.
And it's funny and fun, with plenty of adventure and fighting and clever, clever political moves on the part of the Patrician.
Great stuff, with trains in, plenty of train-loving by enthusiastic fans of the new engines. This is geek love.
Personal copy.