Method for monitoring a drive system of a rail vehicle to identify a break of or damage to a coupling (K1-K4) of the drive system, wherein the drive system has at least two drive trains (AS1-AS4) each with at least one electric drive motor (M1-M4) and a coupling (K1-K4), at least one inverter (WR) feeding the at least two drive motors (M1-M4) together, as well as a control facility (ST), wherein the at least two drive motors (M1-M3) are embodied as three-phase asynchronous machines, with the steps: for each of the at least two drive trains (AS1-AS4), detecting at least one drive-side rotary speed (nm1-nm4) and at least one load-side rotary speed (n k1 -n k4 , n g1 -n g4 ) of the coupling (K1-K4), for each of the at least two drive trains (AS1-AS4), ascertaining at least one value of a slip (s1-s4) of the coupling (K1-K4) from the detected rotary speeds (n m1 -n m4 , n k1 -n k4 , n g1 -n g4 ), for each of the at least two drive trains (AS1-AS4), comparing the at least one ascertained value of the slip (s) with a predefined threshold value, wherein the threshold value is defined as a function of a frequency of a rotary field of the drive motor, and initiating at least one measure for protecting the drive system as a function of a result of the respective comparison. the drive system has at least two drive trains (AS1-AS4) each with at least one electric drive motor (M1-M4) and a coupling (K1-K4), at least one inverter (WR) feeding the at least two drive motors (M1-M4) together, as well as a control facility (ST), wherein the at least two drive motors (M1-M3) are embodied as three-phase asynchronous machines, with the steps: for each of the at least two drive trains (AS1-AS4), detecting at least one drive-side rotary speed (nm1-nm4) and at least one load-side rotary speed (n k1 -n k4 , n g1 -n g4 ) of the coupling (K1-K4), for each of the at least two drive trains (AS1-AS4), ascertaining at least one value of a slip (s1-s4) of the coupling (K1-K4) from the detected rotary speeds (n m1 -n m4 , n k1 -n k4 , n g1 -n g4 ), for each of the at least two drive trains (AS1-AS4), comparing the at least one ascertained value of the slip (s) with a predefined threshold value, wherein the threshold value is defined as a function of a frequency of a rotary field of the drive motor, and initiating at least one measure for protecting the drive system as a function of a result of the respective comparison. for each of the at least two drive trains (AS1-AS4), detecting at least one drive-side rotary speed (nm1-nm4) and at least one load-side rotary speed (n k1 -n k4 , n g1 -n g4 ) of the coupling (K1-K4), for each of the at least two drive trains (AS1-AS4), ascertaining at least one value of a slip (s1-s4) of the coupling (K1-K4) from the detected rotary speeds (n m1 -n m4 , n k1 -n k4 , n g1 -n g4 ), for each of the at least two drive trains (AS1-AS4), comparing the at least one ascertained value of the slip (s) with a predefined threshold value, wherein the threshold value is defined as a function of a frequency of a rotary field of the drive motor, and initiating at least one measure for protecting the drive system as a function of a result of the respective comparison. <EOS>