When building a railway model you can from the Railway Cross-section Wizard choose to also add the profile of the train.
You will then see a 3D train as part of your 3D geometries in Quadri, and also see the train profile in your cross-section viewer. If such a profile has been added you can then also draw it out in your CAD drawing with the Draw 3D Train tool. It will be drawn as a lofted solid or surface, and you can choose to draw it with or without the ballast.