This chapter describes the different electric railway power supply systems and their main characteristics from the point of view of the power flow modeling and simulation. It considers the DC traction systems and also the AC ones, explaining the different elements embedded in the network and proposing steady state electrical models of each element. The basic methods for modeling the train behavior in terms of demanded/regenerated power are also detailed. Finally, the procedures to simulate the trains motion into the electrical network and how their motion and power demand affect to the electrical variables will be unraveled, explaining how to merge all the models in a system of equations.
