Between May and July 1959, the South African Railways placed seven Class 1-DH Henschel type DH-1420 diesel-hydraulic locomotives in service to also gain experience with other forms of diesel motive power than diesel-electric.

[1] The Class 61-000 type DH-1420 diesel-hydraulic locomotive was designed and built for the South African Railways (SAR) by Henschel & Son in Kassel, Germany.

[1] The more commonly used diesel-electric locomotive makes use of a diesel engine prime mover to propel either a generator (DC) or an alternator (AC) to generate electric power, which is then used to propel axle-hung electric traction motors, one per powered axle, to drive the locomotive wheels.

[1] The diesel-hydraulics were acquired to enable a direct comparison with the Class 31-000 General Electric-built diesel-electrics, but these Henschel machines did not perform as well.

Although it has been surmised that the much higher ambient temperatures in South Africa might have been a factor, an improved cooling system could probably have solved that if it had been the main problem.

[5][6][7][8] The Class 61-000s spent their entire SAR working lives stationed at the Germiston diesel depot.

61-006} was involved in a head-on collision at Kaserne on 8 October 1966 and was eventually scrapped at the Koedoespoort workshops in Pretoria in September 1968.