ing ▁on ▁the ▁central ▁bog ie , ▁which ▁is ▁very ▁well ▁su ited ▁for ▁the ▁often ▁tort uous ▁lines ▁of ▁Italy ▁and ▁that ▁would ▁have ▁been ▁later ▁repeated ▁on ▁the ▁E . 6 4 5 / 6 4 6 ▁and ▁E . 6 5 6 ▁classes . ▁The ▁presence ▁of ▁a ▁great ▁number ▁of ▁whe els ▁was ▁considered ▁important ▁due ▁to ▁the ▁presence ▁of ▁a ▁number ▁of ▁high - s lo pe ▁lines ▁in ▁the ▁Italian ▁rail road ▁network ▁as ▁it ▁increases ▁the ▁ad hes ion ▁limit , ▁meaning ▁that ▁the ▁locomot ive ▁is ▁less ▁pr one ▁to ▁wheel ▁sli ps . ▁The ▁new ▁engines ▁weight ed ▁approximately ▁. ▁Eng ines ▁were ▁initially ▁the ▁same ▁as ▁E . 6 2 6 . ▁The ▁ 3 2 R ▁used ▁a ▁ 3   k V ▁c aten ary ▁but ▁this ▁was ▁soon ▁shown ▁to ▁be ▁in ade qu ate ▁and ▁so ▁were ▁updated ▁and ▁provided ▁with ▁a ▁new ▁h ollow ▁ax le ▁transmission ▁system . ▁Main ly ▁two ▁different ▁g ear ▁r ati os ▁were ▁installed : ▁ 2 1 / 6 5 ▁for ▁s lop ing ▁lines ▁or ▁heavy ▁fre ight ▁trains ▁( maxim um ▁speed ▁of ▁, ▁elev ated ▁later ▁to ▁ 1 1 0   km / h ), ▁and ▁the ▁longer ▁ 2 8 / 6 5 , ▁with ▁a ▁maximum ▁speed ▁of ▁, ▁su ited ▁for ▁passenger ▁services . ▁ ▁The ▁locomot ive ▁was ▁built ▁in ▁three ▁different ▁series : ▁ 1 st ▁series ▁( 0 0 1 -