▁sets . ▁ ▁History ▁The ▁prototype ▁set , ▁ 1 0 - 0 1 0 , ▁was ▁built ▁in ▁ 1 9 7 1 , ▁and ▁initially ▁tested ▁on ▁the ▁To ei ▁M ita ▁Line . ▁ ▁Ref urb ishment ▁comm enced ▁in ▁fis cal ▁ 2 0 0 9 . ▁This ▁consisted ▁of ▁adding ▁external ▁speak ers , ▁replacing ▁the ▁original ▁roll er ▁blind ▁destination ▁indic ators ▁with ▁LED ▁indic ators , ▁moving ▁the ▁body ▁side ▁destination ▁indic ators ▁from ▁the ▁ends ▁to ▁a ▁central ▁position , ▁and ▁adding ▁interior ▁passenger ▁information ▁displays . ▁ ▁In ▁ 2 0 0 5 ▁and ▁ 2 0 0 6 , ▁the ▁ 1 0 - xx 7 ▁and ▁ 1 0 - xx 8 ▁cars ▁of ▁sets ▁ 1 0 - 0 1 0 ▁to ▁ 1 0 - 1 8 0 ▁were ▁ref urb ished ▁and ▁reform ed ▁with ▁new ▁driving ▁cars ▁to ▁become ▁ 1 0 - 3 0 0 R ▁series . ▁These ▁cars ▁were ▁built ▁between ▁ 1 9 8 6 ▁and ▁ 1 9 8 9 ▁as ▁batch es ▁ 3 ▁and ▁ 5 ▁to ▁length en ▁original ▁ 6 - car ▁sets ▁to ▁ 8 ▁cars , ▁and ▁so ▁were ▁still ▁relatively ▁new ▁compared ▁to ▁the ▁rest ▁of ▁the ▁cars ▁in ▁the ▁sets ▁in ▁which ▁they ▁were ▁contained . ▁▁ ▁The ▁final ▁set , ▁ 1 0 - 2 8 0 , ▁was ▁retired ▁on ▁ 1 1 ▁February ▁ 2 0 1 8 . ▁ ▁Build ▁details