the gas operated drive motor 15 and vents the output 17 of the gas operated drive motor 15 through an exhaust port 20 to the atmosphere so that the drive shaft 16 of the gas operated drive motor 15 rotates in a direction defined as its forward direction in its second setting however the reverse flow valve 19 conducts the gas from the output 13 of the variable pressure reservoir 12 to the output 17 of the gas operated drive motor 15 and vents the input 14 of the gas operated drive motor 15 through the exhaust port 20 to the atmosphere so that the gas flows through the gas operated drive motor 15 in a direction opposite to that when the reverse flow valve 19 is in its first setting thereby causing the drive shaft 16 of the gas operated drive motor 15 to rotate in its reverse direction a third setting of the reverse flow valve 19 provides a braking mode for the optimized gas based transmission besides being connected to the high pressure reservoir 1 through the variable pressure reservoir 12 and the first pressure regulator 6 the reverse flow valve 19 is connected to a second check valve 21 which is in turn attached to a secondary input 22 of the high pressure reservoir 1 when the reverse flow valve 19 is in its third setting the neutral valve 18 is placed in its second setting to direct the exhaust gas 2 from the engine 3 to the atmosphere thereby making the engine resistance.