Method for diagnosing rotating components of a railway vehicle, the railway vehicle including a plurality of wheels (7, 7a, 7b), a plurality of rotating components, at least one sensor (5a - 5d) mounted on at least one of the plurality of rotating components, and at least one diagnostic device, the method comprising the following steps carried out by the at least one diagnostic device: - receiving a measuring signal from a sensor (5a - 5d) mounted on a rotating component; - determining a frequency spectrum of the measuring signal; - receiving a velocity of the railway vehicle, wherein the velocity of the railway vehicle is determined from global navigation satellite system data or received from a vehicle control unit of the railway vehicle; - determining a rotation frequency of the rotating component based on the railway vehicle velocity and a diameter of a wheel (7, 7a, 7b) of the railway vehicle; - determining a characteristic frequency of the rotating component based on component parameters and the determined rotation frequency; - determining a signal amplitude of the frequency spectrum of the measuring signal at the characteristic frequency; - comparing the determined signal amplitude with a reference value; detecting a failure if the signal amplitude exceeds the reference value, wherein the wheel diameter for determining the rotation frequency of the rotating component is updated at predetermined time intervals, wherein the wheel diameter is measured in a first predetermined time interval when a regular inspection of the railway vehicle is carried out and is inputted into the diagnostic device after the measurement, and/or the wheel diameter is measured automatically in a second predetermined time interval and is inputted into the diagnostic device after the measurement. the method comprising the following steps carried out by the at least one diagnostic device: - receiving a measuring signal from a sensor (5a - 5d) mounted on a rotating component; - determining a frequency spectrum of the measuring signal; - receiving a velocity of the railway vehicle, wherein the velocity of the railway vehicle is determined from global navigation satellite system data or received from a vehicle control unit of the railway vehicle; - determining a rotation frequency of the rotating component based on the railway vehicle velocity and a diameter of a wheel (7, 7a, 7b) of the railway vehicle; - determining a characteristic frequency of the rotating component based on component parameters and the determined rotation frequency; - determining a signal amplitude of the frequency spectrum of the measuring signal at the characteristic frequency; - comparing the determined signal amplitude with a reference value; - receiving a measuring signal from a sensor (5a - 5d) mounted on a rotating component; - determining a frequency spectrum of the measuring signal; - receiving a velocity of the railway vehicle, wherein the velocity of the railway vehicle is determined from global navigation satellite system data or received from a vehicle control unit of the railway vehicle; - determining a rotation frequency of the rotating component based on the railway vehicle velocity and a diameter of a wheel (7, 7a, 7b) of the railway vehicle; - determining a characteristic frequency of the rotating component based on component parameters and the determined rotation frequency; - determining a signal amplitude of the frequency spectrum of the measuring signal at the characteristic frequency; - comparing the determined signal amplitude with a reference value; detecting a failure if the signal amplitude exceeds the reference value, wherein the wheel diameter for determining the rotation frequency of the rotating component is updated at predetermined time intervals, wherein the wheel diameter is measured in a first predetermined time interval when a regular inspection of the railway vehicle is carried out and is inputted into the diagnostic device after the measurement, and/or the wheel diameter is measured automatically in a second predetermined time interval and is inputted into the diagnostic device after the measurement.