▁K ew dale - K win ana ▁line ▁was ▁constructed ▁between ▁K ew dale ▁and ▁the ▁Spe ar wood - C ock burn ▁C ement ▁line ▁at ▁C ock burn , ▁and ▁the ▁C ock burn ▁C ement ▁line ▁extended ▁south ▁to ▁intersect ▁with ▁the ▁Rob bs ▁Jet ty - K win ana ▁line ▁at ▁Naval ▁Base . ▁A ▁mar sh alling ▁yard ▁was ▁constructed ▁south ▁of ▁Rock ingham ▁Road . ▁The ▁Spe ar wood - C ock burn ▁C ement ▁line ▁and ▁Rob bs ▁Jet ty - Spe ar wood ▁line ▁was ▁converted ▁to ▁dual ▁gauge , ▁and ▁continued ▁north ▁to ▁F rem ant le ▁and ▁the ▁mar sh alling ▁yards ▁at ▁Le ight on . ▁The ▁Rob bs ▁Jet ty - Co og ee ▁line ▁to ▁Wood man ▁Point ▁( now ▁removed ) ▁was ▁converted ▁to ▁dual ▁gauge . ▁The ▁K win ana ▁loop ▁rail ▁was ▁constructed ▁at ▁dual ▁gauge . ▁ ▁The ▁rail ways ▁constructed ▁and ▁upgrad ed ▁under ▁the ▁Rail ways ▁( Standard ▁G au ge ) ▁Const ruction ▁Act ▁ 1 9 6 1 ▁form ▁the ▁back bone ▁of ▁the ▁fre ight ▁railway ▁network ▁in ▁Per th . ▁ ▁K win ana ▁Loop ▁ ▁The ▁K win ana ▁Loop ▁Railway ▁is ▁railway ▁branch ing ▁from ▁the ▁main ▁line ▁at ▁K win ana ▁first ▁constructed ▁under ▁the ▁Indust rial ▁Land s ▁( K win ana ) ▁Railway ▁Act ▁ 1 9 6 6 ▁and ▁later ▁extended ▁to ▁the ▁C B H ▁Group ▁terminal ▁under ▁the ▁K win ana ▁Loop