If you're interested in this period of railway history then buying this book is a no-brainer, however I don't think I can recommend it to anyone with only a casual interest in railways.
My problem with this book is the way it's written. Each chapter reads less like a broad history and more like a disorganised fact file, often full of hyper specific statistics that I don't think are really needed. This unfortunately means that (in my opinion), it's not an especially easy or at times even fun book to read.
That being said, there's still a great deal of content within its pages. The author is an excellent historian and the book is very well researched, I just wish the information was presented in a more digestible manor.