Along with detailed diagrams, this book contains handy overall maps, including one showing the sequence of line closures.
Beware, though, that as the book follows the Rhymney Valley towards Machen, neither the Darran valley nor Rhymney Railway south of Pengam are shown.
See our review: ‘Track Layout Diagrams of the GWR & BR WR: Section 42, Rhymney Valley’ by R. A. Cooke