In recent years, energy efficiency has become a crucial concern for every transportation mode, but it is in electrified railways where energy savings have shown a bigger potential due to (i) regenerative braking, that allows converting kinetic energy into electric power, and (ii) vehicle interconnection, that allows other trains to use regenerated power. Power supply and energy management will continue to develop in the future. This book gathers under a single cover several papers published in the Computer on Railways series (IX, X and XI) and focuses on power supply and energy management. Some of the discussed themes are: modelling, simulation and optimisation of AC and DC infrastructure, analysis of rolling stock consumption, and innovative approaches in power supply operation. This book will be invaluable to management consultants, engineers, planners, designers, manufacturers, operators and IT specialists who need to keep abreast of the latest developments in the field.