I liked the parts about the railway signaling, and suffered through all the multi-page anti-regulatory rants in the middle of lovemaking. Looking for recommendations for entertaining tales of signal networks. :P
In addition to the invention of a working mail system, you’ll read descriptions of semaphore towers working in a way that is similar to the Telegraph, except with light rather than pulsed waves over wire. It’s also hilariously funny and deeply philosophical at times.
I recommend it wholeheartedly.
The first discworld book I read was Thief of Time, and I've been hooked ever since