, ▁later ▁designated ▁North ▁Island ▁Main ▁Tr unk ▁first - class ▁carri ages , ▁for ▁express es ▁on ▁this ▁route , ▁two ▁( with ▁staff ▁and ▁host ess ▁compart ments ▁retained ▁and ▁augment ed ) ▁as ▁the ▁South ▁Island ▁Main ▁Tr unk ▁Main ▁South ▁Line ▁single - lav atory ▁ 2 9 ▁seat ▁equivalent , ▁along ▁with ▁four ▁ 1 6 - ber th ▁sleep ing ▁carri ages . ▁In ▁their ▁ref urb ished ▁form , ▁the ▁day ▁carri ages ▁se ated ▁ 3 0 ▁in ▁the ▁same ▁type ▁of ▁" bucket " ▁seat ▁and ▁the ▁day ▁cars ▁with ▁staff ▁compart ments ▁se ated ▁ 2 5 . ▁The ▁sleep ing ▁carri ages ▁still ▁each ▁accommod ated ▁ 1 6 ▁( 2 ▁ber th s ▁in ▁ 8 ▁cab ins ). ▁In ▁ 1 9 7 3 ▁larger ▁train ▁sets ▁were ▁planned ▁with ▁the ▁fitting ▁of ▁ 2 0 ▁first - class ▁and ▁sleep ing ▁cars ▁with ▁he aters . ▁The ▁final ▁fit - out ▁of ▁the ▁train ▁was ▁not ▁approved ▁until ▁November ▁ 1 9 7 4 ▁with ▁instructions ▁to ▁complete ▁the ▁re build ▁of ▁the ▁minimum ▁rolling ▁stock ▁for ▁the ▁introduction ▁of ▁the ▁express ▁replacement ▁within ▁ 1 2 ▁months . ▁ ▁Three ▁d ining ▁carri ages ▁were ▁created ▁from ▁ 1 9 6 0 s ▁built ▁ ▁long ▁ ▁al umin ium - she athed ▁Railway ▁Tra v elling ▁Post ▁Office ▁v ans . ▁These ▁vehicles ▁each ▁se ated ▁ 4 0 ▁in ▁tip - up ▁ben ch ▁type ▁seats