An EMS (ElectroMagnetic Suspension) system is a complex control system, consisting of many interacting subsystems. For control design, there is an obvious trade-off between design complexity and performance, just as there is a trade-off between model complexity and its utility. In this paper, we represent three mathematic models of an EMS system, and demonstrate theoretically that the model based on “half bogie” EMS subsystem captures the dynamics sufficiently to obtain a high performing controller. From a control design point of view, there is no need to model at the full bogie or multiple bogie system level, on the contrary.