▁this , ▁the ▁engines ▁were ▁trouble - free ▁and ▁gave ▁more ▁than ▁sevent y ▁years ▁of ▁service . ▁After ▁withdraw al , ▁many ▁were ▁sold ▁into ▁industrial ▁service ▁and ▁some ▁of ▁these ▁reached ▁almost ▁ 1 0 0 ▁years ▁in ▁service . ▁ ▁The ▁Class ▁ 1 1 ▁were ▁powerful ▁locomot ives ▁which ▁gave ▁good ▁service ▁at ▁moder ate ▁spe eds , ▁but ▁at ▁higher ▁speed ▁the ▁light ly ▁loaded ▁leading ▁B iss el ▁tr uck ▁with ▁its ▁ ▁ax le ▁load ▁proved ▁uns atisf actory ▁on ▁curves . ▁ ▁South ▁African ▁Rail ways ▁When ▁the ▁Union ▁of ▁South ▁Africa ▁was ▁established ▁on ▁ 3 1 ▁May ▁ 1 9 1 0 , ▁the ▁three ▁Col onial ▁government ▁rail ways ▁( C ape ▁Government ▁Rail ways , ▁Natal ▁Government ▁Rail ways ▁and ▁CS AR ) ▁were ▁un ited ▁under ▁a ▁single ▁administration ▁to ▁control ▁and ▁admin ister ▁the ▁rail ways , ▁ports ▁and ▁har b ours ▁of ▁the ▁Union . ▁Although ▁the ▁South ▁African ▁Rail ways ▁and ▁Har b ours ▁came ▁into ▁existence ▁in ▁ 1 9 1 0 , ▁the ▁actual ▁classification ▁and ▁ren umber ing ▁of ▁all ▁the ▁rolling ▁stock ▁of ▁the ▁three ▁constitu ent ▁rail ways ▁were ▁only ▁implemented ▁with ▁effect ▁from ▁ 1 ▁January ▁ 1 9 1 2 . ▁ ▁In ▁ 1 9 1 2 , ▁the ▁CS AR ▁Class ▁ 1 1 ▁locomot ives ▁were ▁ren umber ed ▁in ▁the ▁range ▁from ▁ 9 1 2 ▁to ▁ 9 4 7 , ▁but ▁their ▁Class ▁