Abstract: Apparatus for electronically simulating the response of a direct current traction motor to predetermined operating states whereby there is provided a resultant signal representative of the torque that would be produced by an actual motor operating in the prescribed states. The apparatus calculates E per RPM for the simulated motor from measured values of available armature voltage and armature velocity. A function generator thereafter converts the E per RPM signal to a signal representative of the motor field current based upon known values for the simulated motor. The field current signal is converted to an armature current signal by a circuit which responds to the motor commanded state of field weakening to compute the instantaneous ratio of armature current to field current under the commanded conditions and thereafter multiplies the field current signal by that ratio to obtain a signal representative of armature current.