 As built, the Class had a fuel tank and interlinked bogies, while the Class was delivered new to Iscor with a fuel tank to cope with the lack of en route refuelling points on the Sishen-Saldanha iron ore line.To facilitate the larger fuel tank, the inter-bogie linkage found on all other models had to be omitted on the Class 34-500.To be usable on the iron ore line, Class units which ended up working there were modified to a similar fuel capacity.