The　turnout　is　the　key　equipment　for　guiding　trains　to　change　lines　in　railway　track,　which　can　affect　the　vehicle　running　smoothness　and　limit　the　train　speed　drastically.　This　paper　proposes　an　optimisation　method　for　turnout　layout　of　the　diverging　route　by　considering　multiple　curvatures　or　curvature　changes　through　the　vehicle-turnout　dynamics,　and　the　effect　of　train　speed　on　dynamic　response　is studied.　For　the　small　numbered　turnout,　increasing　the　curve　radius　of　a　single　circular　curve　type　or　using　a　double　radii　curves　type　with　a　larger　front　radius　can　effectively　reduce　the　increase　in　wheel–rail　forces　and　improve　train　running　quality.　For　the　large　numbered　turnout,　the　transition　curve　can　be　added　to　the　diverging　route　to　form　a　circular–transition　curve　or　a　transition–circular–transition　curve　type,　thereby　significantly　reducing　the　dynamic　response　of　the　vehicle-turnout　system.　The　wheel–rail　dynamic　response　increases　approximately　linearly　with　the　train　speed　in　the　circular　curve　of diverging　route,　but　the　increase　rate　decreases　significantly　with　the　train　speed　in　the　transition　curve　part,　which　is　more　conducive　to　the　increase　of　the　train　speed　passing　through　turnouts.　©　2021　Informa　UK　Limited,　trading　as　Taylor　&　Francis　Group.