Method of charging an energy storage unit

The invention concerns a method of charging an energy storage unit of an electric vehicle (1) while the electric vehicle (1) is situated on a part of a railway train (2), as well as an electric power supply (3) installable on board a railway train (2). On a part of a railway train (2), an electric power supply (3) is provided which is adapted to supply electrical energy suitable to charge an energy storage unit of an electric vehicle (1). A transmission of electrical energy from the electric power supply (3) to the electric vehicle (1) is initiated while the electric vehicle (1) is situated on the part of the railway train (2).