The author describes a DC traction motor test regime which has proven highly successful for Queensland Rail (QR), Australia, over the past five years, being initially driven from the commercial view point of preventing costly operational failures of traction machines. The benefits of this policy are now starting to be realised, however, it has been a long process. Such developments are highly dependent on a detailed knowledge of the motor insulation and coil structure. This process of developing nonintrusive test indicators of traction machines is now also being applied to the stator windings of the newer three-phase asynchronous traction machines now starting service in QR. This basis for cost effective maintenance and minimisation of operational failures within QR continues. There is ongoing research into the development of these indicators. Training of QR staff and contractors, in testing for these indicators, observing unusual machine behaviour/test results and deviation from normal operation, continues.