Abstract: An electrical propulsion control system for self-propelled traction vehicles having an electric generator supplying energy to separately excited traction motors, each motor field being normally excited with a substantially constant field excitation providing magnetic saturation such that motor load variations produce minimal changes in back emf, and means for equally boosting the excitation of each motor field responsive to the largest one of the individual motor armature currents exceeding a predetermined magnitude which is greater than the maximum attainable armature current during dynamic retarding operation.