Abstract: A system, method and apparatus for multi-fuel, range extending power generation applied to propulsion in a vehicle. One or more fluid fuels including diesel and natural gas and/or their renewable counterparts of Biodiesel or Renewable Natural Gas are stored on board a vehicle and selectively supplied to an onboard electrical generator according to sensor measurements analyzed by a processor directing power generation and transmission to motor controllers and motors providing vehicle propulsion. The combined natural gas-electric and diesel-electric transmissions control system power generation driving electric motors rather than a diesel engine mechanical connection to axles and wheels. This integrated system provides improved extended range to diesel hauling applications with improved emissions while maintaining torque, and efficiency.