This application relates to a cutting insert and method for machining a workpiece. This application further relates to a method for the machining of a workpiece using such an indexable insert. In this case, the term “machining” means, among other things, the first-time machining and/or a re-profiling of a wheel or of a brake disc of a wheel set of a railway vehicle. An object of at least one possible embodiment of the present application is to create a cutting insert that is as economical as possible. An additional object of at least one possible embodiment of the present application is the most effective method possible and a lathe tool that is well-suited for the machining of a workpiece, such as for the copy turning and/or for the first-time machining and/or for the re-profiling of a wheel or of a brake disc of a wheel set of a railway vehicle, using a cutting insert described herein.