Modelling and simulation

The design of railway power supplies must account for a wide range of factors such as the performance of the rolling stock, the track alignments, the level of service to be provided as well as basic issues such as the choice of AC or DC and the level of supply security desired. The interaction between all these factors is very complex and the only really feasible way to assess proposed designs is by computer simulation. This, in turn, requires the development of suitable mathematical models of the traction equipment, the mechanics of the train performance and the behaviour of the power supply conductors and substations. This paper describes how this modelling is approached and how the equations can be integrated with operational models into a complete multi-train simulation that effectively runs typical services. Power supply loads and voltage drops, for example, can thus be examined.