Abstract: An off-road, heavy duty, haulage vehicle includes a diesel engine driving an alternator (generator) for producing electrical power for motorized rear wheels. An alternator field converter is electrically connected to the alternator and an armature converter and a motor field converter are electrically connected to the two motors of the motorized rear wheels. A computerized control center includes control systems including an alternator field converter control system, a motor field control system, and a vehicle operation and maintenance control system. Tertiary windings are used as a source of excitation and the phase angle controlled armature converter is used in conjunction with alternator voltage control system for holding the alternator at an increment of voltage higher than the motors but not at a constant maximum voltage level.