▁has ▁over ▁a ▁dies el - elect ric ▁variety ▁is ▁its ▁ability ▁to ▁negoti ate ▁up ▁to ▁ 3 0 0 mm ▁of ▁water ▁over ▁the ▁tracks . ▁Big ▁flo ods ▁in ▁March ▁ 1 9 7 6 ▁gave ▁ 7 3 2 3 ▁an ▁opportunity ▁to ▁show ▁off ▁its ▁sw imming ▁ability ▁when ▁water ▁covered ▁the ▁line ▁near ▁Bour ke ▁and ▁this ▁locomot ive ▁was ▁used ▁on ▁a ▁couple ▁of ▁fre ight ▁trains ▁and ▁a ▁ball ast ▁train ▁from ▁Ny ng an ▁to ▁Bour ke ▁and ▁return . ▁At ▁least ▁two ▁other ▁occasions ▁when ▁their ▁water ▁resistance ▁was ▁put ▁to ▁use ▁was ▁Men inde e ▁in ▁ 1 9 7 6 ▁and ▁H ex ham ▁in ▁ 1 9 7 7 . ▁ ▁Multiple ▁unit ▁operation ▁was ▁common , ▁although ▁the ▁flo od ▁event ▁at ▁H ex ham ▁is ▁the ▁only ▁known ▁occurrence ▁of ▁triple - head ing . ▁A ▁number ▁of ▁units ▁were ▁fitted ▁with ▁exhaust ▁gas ▁scr ub bers ▁for ▁use ▁on ▁Eastern ▁Sub ur bs ▁Railway ▁construction ▁in ▁the ▁ 1 9 7 0 s . ▁ ▁Dep ot ▁allocation ▁As ▁an ▁example ▁of ▁the ▁spread ▁of ▁the ▁members ▁of ▁the ▁class ▁throughout ▁the ▁system , ▁the ▁fleet ▁was ▁allocated ▁as ▁follows ▁as ▁at ▁ 3 0 ▁August ▁ 1 9 7 7 : ▁ ▁With draw al ▁ ▁With ▁a ▁reduction ▁in ▁locomot ive ▁ha u led ▁passenger ▁trains ▁and ▁the ▁closure ▁of ▁a ▁number ▁of ▁yards , ▁withdraw als ▁began ▁in ▁February ▁ 1 9 8 7