South African Class 91-000
 The South African Class 91-000 of 1973 is a South African diesel-electric locomotive from the South African Railways era.Between September and December 1973 the South African Railways placed twenty Class 91-000 General Electric type UM6B diesel-electric locomotives in service on its narrow gauge Avontuur Railway line between Port Elizabeth in the Eastern Cape and Avontuur in the Western Cape. Some of them later also worked on the Alfred County Railway line out of Port Shepstone in KwaZulu-Natal.