The wheel-rail interface is fundamental to explain the dynamic running behaviour of a railway vehicle. It shall therefore be understood and among the parameters by which it is characterised, the one called "equivalent conicity" plays an essential role since it allows the satisfactory appreciation of the wheel-rail contact on tangent track and on large-radius curves. It is necessary to have a clear determination procedure for equivalent conicity, which is used in European and national standards and documents (legal and technical). The results shall be consistent. To achieve this, a benchmark calculation is defined. This standard proposes also one possible calculation method, which is not explicitly recommended. This procedure contains reference profiles, profile combinations, tolerances and reference results with tolerance limits and allows to assess the acceptability of a measuring and calculation system including radomand grid- failures of the measuring system. This document does not define limits for the equivalent conicity and gives no tolerances for the shape of the railhead and the wheel profile to get acceptable results of the conicity. For other purposes it can be useful or necessary to use more sophisticated theories - for example by including elastic contact patches or the roll angle of the wheelset due to the lateral movement. These methods are not in the scope of this standard.