Method for determining optimal or maximum permissible speed of rail vehicle

The invention relates to a method for determining an optimal or maximum permissible speed (vopt) of a rail vehicle as a function of a thermal state of at least one friction element (1, 2) of at least one friction brake of the rail vehicle, comprising at least the following steps: a) detecting at least one parameter characterizing a current driving operating situation of the rail vehicle, b) determining or estimating a first influence on the thermal state of the at least one friction element (1, 2) on the basis of the current driving operating situation of the rail vehicle, according to the invention, the method comprises at least the following further steps: c) determining or estimating a second influence on the thermal state of the at least one friction element (1, 2), the second influence, in addition to the first influence, influences the thermal state of the at least one friction element (1, 2) when braking is carried out virtually or theoretically with the defined braking type in the current driving oper