low volume rail 24 the high pressure fuel pump 12 also has an output fuel line 17 connected to a large common rail 18 valve 16 in fuel line 17 determines whether fuel flows from the high pressure fuel pump 12 through fuel line 17 to the large common rail 18 on off solenoid control valves 16 and 30 select between the small and large rails as the operating strategy requires fuel line 21 extends between small volume rail 24 and large volume rail 18 with valve 22 controlling flow in fuel line 21 valve 22 is normally open and pulse width modulated or controlled in an alternative variable method by closing both valves 16 and 22 small volume rail 24 is isolated from large volume rail 18 during the engine starting procedure at which time small total internal rail volume is desired as pressure in the small volume rail 24 approaches a predetermined operating pressure the duty cycle on valve 22 decreases as the pressure in large volume rail approaches that of the small volume rail 24 the duty cycle on valve 22 approaches 0 i e valve 22 is open engine control unit 40 receives inputs from pressure transducers 20 and 26 which are installed in large volume rail 18 and small volume rail 24 respectively valves 16 and 30 are operated opened or closed by engine control unit 40 based on time since engine start or the pressures indicated by transducers 20 and 26 engine control unit 40.