Hybrid powertrain having a selectable by the operator electric drive mode

A drive train for a vehicle including an engine and a transmission having an input member, an output member and a neutral state in which no torque is transmitted from the input member to the output member. A first motor / generator is coupled to the machine. A second motor / generator is coupled through the transmission directly or indirectly to the vehicle wheels. The first motor / generator acts as a generator when it is acted upon by the engine with power in order to supply electric power to the second motor / generator. The second motor / generator acts as a motor when it receives electrical power from a battery or from the first motor / generator. A shift selector is moved by the vehicle operator to establish an electric drive mode in which the transmission is in the neutral condition and functions of the second motor / generator as a motor.