A project was commenced to rebuild the aging _B__ class locomotives. From 1983, eleven units were transferred to the Rosewater, South Australia plant of Clyde for rebuilding.
The units were heavily modified and fitted with 2300hp V12 turbo engines.
Their principal duty was for passenger trains though from the late 1980's the units were rostered for freights as required.
One unit was fitted with high speed gears capable of 160km/hr speed tests.
Unit numbers were: 60, 62, 66, 70, 71, 73, 77, 78, 79, 81, 85.
A 66 was painted in the Australian Bicentennial colours in 1988. In 1990 the unit was painted in Olympic Games colour scheme as part of the Melbourne Olympic Games bid for 1996.