▁time . ▁ 2 0 0 ▁units ▁were ▁therefore ▁re built ▁and ▁stri pped ▁of ▁all ▁as best os . ▁ ▁Starting ▁from ▁the ▁ 1 9 9 0 s , ▁E . 6 3 6 s ▁were ▁used ▁mainly ▁for ▁cargo ▁services , ▁save ▁for ▁the ▁more ▁back log ▁Sic ilian ▁lines . ▁Some ▁units ▁were ▁l ent ▁to ▁minor ▁Italian ▁rail ro ads . ▁The ▁ph asing ▁out ▁of ▁the ▁entire ▁class ▁was ▁completed ▁in ▁May ▁ 2 0 0 6 . ▁ ▁Techn ical ▁details ▁▁ ▁E . 6 3 6 ▁are ▁very ▁simple ▁locomot ives . ▁Most ▁functions ▁of ▁the ▁main ▁command ▁circuit ▁are ▁accomplished ▁through ▁various ▁rel ays ▁and ▁contact ors . ▁In ▁case ▁of ▁failure ▁the ▁train ▁driver ▁could ▁easily ▁fix ▁them ▁to ▁at ▁least ▁free ▁the ▁tracks ; ▁also , ▁especially ▁in ▁last ▁years ▁of ▁their ▁service , ▁E . 6 3 6 s ▁were ▁the ▁first ▁locomot ives ▁that ▁the ▁new ▁train ▁drivers ▁studied ▁during ▁their ▁training ▁courses , ▁due ▁to ▁their ▁simple ▁working ▁mechan ics . ▁ ▁Mot ors ▁and ▁elect rical ▁description ▁▁ ▁As ▁most ▁older ▁Italian ▁locomot ives , ▁E . 6 3 6 ▁has ▁a ▁r he ost at ▁( formed ▁by ▁ 1 6 ▁cast ▁iron ▁resist ors ▁connected ▁in ▁series , ▁for ▁a ▁total ▁resistance ▁of ▁ 2 9 ▁oh ms ) ▁that ▁needs ▁to ▁be ▁gradually , ▁but ▁as ▁soon ▁as ▁possible , ▁ex cluded ▁on ▁start - ups , ▁which ▁regul ates ▁the ▁current ▁to ▁the ▁six