Railway, as one of the most energy-efficient transport, plays an essential role in improving the world’s energy and environmental sustainability. Statistics about rail share of transport activities and the corresponding energy consumption will demonstrate the energy efficiency of railway and indicate the potential of developing railway transport. Therefore, this chapter will provide an overview of the railway's energy consumption and traffic volume shares. Statistics presented in this chapter show that railway energy consumption decreased in these decades while its transport volume kept stable, and the traffic volume share of the railway is extremely large in urban transport. To achieve the goal of carbon neutralization, the European Union and many countries have conducted research projects on railway energy conservation. The technologies developed in these projects include energy-efficient train driving, integrated timetabling, using regenerative braking energy, etc. A summary of these technologies is also given, along with their potential energy savings, which range from 1 to 25%. This book will analyse and illustrate the whole systems processes of train operation with optimisation solutions. The structure of the following chapters will be presented at the end.

This chapter gives the basic conclusions about energy-efficient train operation covering energy-efficient train driving, energy-efficient train timetabling, regenerative braking, energy storage systems and power supply networks. Future work that will develop energy-efficient train operation further include the interaction of connected driver advisory systems (C-DAS) and automatic train operation (ATO) with railway traffic management systems, cooperative train control in platoons of virtually coupled trains, digital twin technology and particularly its application to power supply systems, and the interaction between the railway network with the electrical power grid and renewable energy generation.