This book details many of the different types of infrastructure that are present in a rail system. It is an overview, and presents a reasonable level of depth to the various engineering systems, such as track and signalling. The book discusses at length rail tunnels, and their related infrastructure, which includes the tunnel itself, fire systems, water management, and ventilation. The configuration of different rail tunnels is also discussed, and the advantages and disadvantages of each is also discussed. The book also discusses stations in length as well. The many different aspects of station design are discussed, so as passenger flows through the station. As with tunnels, there are different configurations for stations, which in some cases depend on the tunnel design, should the station be underground. Light rail station design is also discussed. Loading and structure gauges are discussed, as well as definitions of gauges and centre and end throw. Platform heights, which is related to station design, is also discussed. The book also discusses the basics of the structure of signalling. An explanation is provided of some very simple signalling, and track sections are explained. Indications and aspects of signals are also explained. Finally, there is some discussion of infrastructure related to the network design of a rail system, such as stabling yards, and maintenance centres. Signal boxes and control centres are also discussed.