 Since 1969, the ore trains have been using the Soviet SA3 coupler.However, LKAB wanted to also try Janney couplers (also known as AAR coupler, used in much heavier trains in USA and South Africa), as the SA3 couplers were not much tested with the new weights.While the first pair of locomotives had Janney couplers, the rest of the locomotives were equipped with SA3 couplers to handle the existing hopper cars, and the cars bought from K-Industrier.