A couple of points YM
It was merely to indicate that finding modern day facts was/is slightly more difficult. It appears to me that the earlier days seem to provide the more interesting facts and figures, but that could just be me.
Also, as readers will find out as the facts continue, it is hard to draw comparisons with different eras.
When the TAR was first built is was primarily a passenger line with the only competition being going on a sometimes treacherous sea voyage from the eastern states to Perth/Fremantle.
The line was then used more and more by the public and further on down the track it was used a great deal by employees either travelling for work, travelling for recreation (from line locations back to Port Augusta/Adelaide or Kalgoorlie/Perth) or using the "pass system" for employees. It was also a time when train travel was more affordable and a popular form of travel or holiday experience.
Today it is back to the travelling public with money, time on their hands or those who prefer "the trip rather than the destination". The numbers travelling today compare to the early 1920's and are about 1/6 of the record numbers using the line in the 1970's. But, as I say, even the facts can be misleading.