There is provided a control system for a powertrain system including an electro-mechanical transmission that is selectively operative in a plurality of fixed gear modes and continuously variable modes. The control system is adapted to identify preferred operating conditions for operating the powertrain in a fixed gear operating range state. The method comprises determining a range of permissible input torques and motor torques input from a first electrical machine to the transmission, and determining a plurality of motor torques input from a second electrical machines based thereupon. Costs are determined, based upon the engine inputs and the motor torques for the first and second electrical machines determined thereupon. A preferred input torque input and a preferred motor torque input is identified based upon the determined costs.