—This paper illustrates the use of the Experiment Design technique applied to the optimization of an electromagnetic brake. In order to place this device in rolling stock application, this study shows the influence of particular characteristic dimensions on the braking and attractive forces. The aim is to determine accurately the variations of these forces especially around the optimal point using the 3D finite element method. A comparison with the experimental measurements is realised in order to validate the model. Index Terms—Eddy current brake, experimental design method, braking and attractive forces, optimization, polynomial model.