▁The ▁gy ro ▁mass , ▁according ▁to ▁B ren nan , ▁accounts ▁for ▁ 3 – 5 % ▁of ▁the ▁vehicle ▁weight , ▁which ▁is ▁compar able ▁to ▁the ▁bog ie ▁weight ▁saved ▁in ▁using ▁a ▁single ▁track ▁design . ▁ ▁Pot ential ▁for ▁high ▁speed ▁▁ ▁High ▁speed ▁convention ally ▁requires ▁straight ▁track , ▁introdu cing ▁a ▁right ▁of ▁way ▁problem ▁in ▁developed ▁countries . ▁W heel ▁profiles ▁which ▁permit ▁sharp ▁corner ing ▁tend ▁to ▁encounter ▁the ▁classical ▁hunting ▁oscill ation ▁at ▁low ▁spe eds . ▁Running ▁on ▁a ▁single ▁rail ▁is ▁an ▁effective ▁means ▁to ▁suppress ▁hunting . ▁ ▁Turn ing ▁corners ▁ ▁Consider ing ▁a ▁vehicle ▁negoti ating ▁a ▁horizontal ▁curve , ▁the ▁most ▁serious ▁problems ▁arise ▁if ▁the ▁gy ro ▁axis ▁is ▁vertical . ▁There ▁is ▁a ▁component ▁of ▁turn ▁rate ▁ ▁acting ▁about ▁the ▁g im bal ▁pivot , ▁so ▁that ▁an ▁additional ▁gy ro scop ic ▁moment ▁is ▁introduced ▁into ▁the ▁roll ▁equation : ▁ ▁This ▁disp laces ▁the ▁roll ▁from ▁the ▁correct ▁bank ▁angle ▁for ▁the ▁turn , ▁but ▁more ▁seriously , ▁changes ▁the ▁constant ▁term ▁in ▁the ▁characteristic ▁equation ▁to : ▁ ▁Ev ident ly , ▁if ▁the ▁turn ▁rate ▁exceed s ▁a ▁critical ▁value : ▁ ▁The ▁bal ancing ▁loop ▁will ▁become ▁un stable . ▁However , ▁an ▁identical ▁gy ro ▁spin ning ▁in ▁the ▁opposite ▁sense ▁will ▁cancel ▁the ▁roll ▁tor que ▁which ▁is ▁causing ▁the ▁inst ability , ▁and ▁if ▁it ▁is ▁forced ▁to ▁pre cess ▁in ▁the ▁opposite ▁direction ▁to ▁the