The aspect of Australian conditions is more relevant than thought, primarily owing to the different temperature extremes along with the terrain here I Australia, and that applies very much to NSW.
Consider the summer temperatures in Australia all over, and especially NSW in this case, compare them to Europe and those countries that have temps anywhere near we do, likewise the terrain/grade and the like. The classic examples of summer temps, extremes and the like especially in summer can be found especially in England where there are warnings issued for older people to be careful in going out when the temps reach 28degree, a further warning is issued with the recommendation that elderly and those not well should stay indoors when it reaches 30degrees. I would love a summer where we did not get over 30 or better still 28.
We had issues on the XPT and their predecessors in the Deb sets especially on the Main North, from Wingen - Ardglen, and then from Limbri - Woolbrook in the summer owing to the need of being in high throttle range in the hot summer weather where it was a juggling issue in maintaining the T/Table with consideration of the motors and their heating. On flatter terrain and even at higher speeds, not that we got to the max very often, you were not in full throttle for long periods.
The old Deb Sets and even the CPH that worked the Wollongong - Moss Vale link had to have extended radiators also to stop at Summit Tank to top the water up. Both are now gone but the Deb sets in particular were juggling acts and problematic in maintaining their timetables, The Debs had problems on the same grades as the XPT but in addition they had them on the 1:40's north of Armidale. There also was always extra oils placed at Glenn Innes and Tenterfield for the motors and transmission's just in case.
Its likely that motors these days are better but the aspect of climate considerations for this country is certainly something to be included in the specs.
CAF train's are made and operate in spain which has a similar temperature climate to Australia. So again there is no reason to consider what the UK is doing with their caf trains is applicable to what CAF will provide to Australia. CAF knows about the AC requirements for Australia because they have made trams for our light rail systems. We will have to see about reliability but these new trains are the way forward especially if it makes regional rail more affordable.