Downer EDI Rail GT46C ACe - Design

Design

The class was a new and innovative design for Australian conditions based on other locomotives produced by Downer EDi, such as the GT42CU AC purchased by Queensland Rail as the 4000 class and the GT46C purchased by Westrail, FreightLink and Freight Australia. The QR 4000 class used a 12-cylinder EMD 710 engine, based on the USA built SD70MAC with scaled down traction motors, while the GT46C used a 16-cylinder EMD 710 engine with DC traction systems. The American SD70ACe was EMD's 2nd generation AC loco with IGBT inverters, but was too large and heavy for the Australian interstate standard gauge network, weighting in at 188 tonnes when the limit was 134 tonnes. In addition, the GT46C design was already at the 134 tonne limit, even before adding inverters, heavier traction motors and more cooling capacity for higher power engine, and there was a requirement that fuel capacity could not be sacrificed.

The locomotive has AC traction equipment, with a Mitsubishi Electric package also used on the SD70ACe, including a TA17 traction alternator, CA9E companion alternator and six ITB 2630 traction motors, along with solid state IGBT inverters. The prime mover is a turbocharged 16-cylinder EMD 710. New technology used included passive steer bogies, to reduce flange wear on corners. The class were built at Cardiff Workshops, with the frames constructed at Port Augusta, and the bogie frames at Kelso.