▁Royal ▁Navy ▁and ▁British ▁Rail ways ▁set ▁up ▁their ▁own ▁work sh ops ▁for ▁over ha uls . ▁ ▁Tur bo - comp ound ▁D elt ic ▁ ▁The ▁" E . 1 8 5 " ▁or ▁" Comp ound ▁D elt ic " ▁tur bo - comp ound ▁variant ▁was ▁planned ▁and ▁a ▁single ▁prototype ▁was ▁built ▁in ▁ 1 9 5 6 ▁and ▁tested ▁in ▁ 1 9 5 7 . ▁This ▁capital ised ▁on ▁Nap ier ' s ▁experience ▁with ▁both ▁the ▁" N om ad " ▁and ▁its ▁increasing ▁invol vement ▁with ▁gas ▁tur b ines . ▁It ▁used ▁the ▁D elt ic ▁as ▁the ▁gas ▁generator ▁inside ▁a ▁gas ▁tur bine , ▁with ▁both ▁a ▁twelve - stage ▁ax ial ▁compress or ▁and ▁a ▁three - stage ▁gas ▁tur bine . ▁Un like ▁the ▁Nom ad , ▁this ▁tur bine ▁was ▁not ▁mechan ically ▁couple d ▁to ▁the ▁c rank sh aft , ▁but ▁merely ▁drove ▁the ▁compress or . ▁It ▁was ▁hoped ▁that ▁it ▁would ▁produce ▁ 6 , 0 0 0 ▁horse power , ▁with ▁fuel ▁economy ▁and ▁power - to - weight ▁ratio ▁" second ▁to ▁none ". ▁Pred ict ions ▁by ▁the ▁engine ers ▁closely ▁connected ▁with ▁it ▁were ▁that ▁connecting ▁rod ▁failure ▁would ▁be ▁the ▁limit ▁on ▁this ▁power , ▁failing ▁at ▁around ▁ 5 , 3 0 0   b hp . ▁On ▁test ▁it ▁actually ▁produced ▁ 5 , 6 0 0   b hp ▁before ▁throwing ▁a ▁connecting ▁rod ▁through