Christian Wolmar tackles his chosen subject without delving into the "rivet-counting" detail that often characterises the genre. As with his previous books, he consciously tries to provide a more rounded overview of the topic, considering the social, financial, political and economic drivers and effects of railway development. With such a potentially huge subject, he opts to present this through a number of case studies, and one of the advantages of doing this is that one can learn of the more obscure topics, such as the railways in New Zealand or the trans-Andean railways. Almost inevitably, however, this means that there is some overlap with some of his previous books, and I was often left wanting to know more (he does, thankfully, provide a brief commentary on where one might go to fulfil this desire).
The most dominant theme in the book is that of the great transcontinental lines, from those in North America to the most recently completed line (the Ghan, running north to south across Australia), and he contrasts the motivations and implications of building these lines very well indeed. Although there are relatively few maps, this book is less about exactly where the railways went, than about why and how they were built, and what effects they had on the continents, and so I never felt truly lost. With a writing style that is easy, very little effort is needed to keep reading.
I would recommend this book to anyone with more than a passing interest in the railways, particularly if they have been avoiding those deeply technical volumes that often crowd the transport sections of bookshops.