I think it worth remembering the Australian context was very different
to other countries.
We are all attuned to thinking that Australia had a sparse network of
railways, because of our small population and vast distances.
Certainly this data from the Australian Yearbook in 1920 supports
that. The yearbook compares different countries, giving a figure of
miles of railway per 1000 square miles of land area:
United Kingdom 195.05
United States 89.57
Of course it is people that buy tickets and dispatch freight, not
square miles of land, so the yearbook also compared miles of railway
per 1000 persons:
United Kingdom 0.5
United States 2.53
So the average Australian had to support twice as much railway line as
the average American, and almost 10 times as much as the average Brit.
No wonder State governments discouraged competition! BTW, Australia
had the highest density of any of the 20 or so countries mentioned in
the article, with only Canada coming close.
OTOH India had both a low density in both categories. This combined
with low transfer costs due to low labour costs, probably explains why
India's narrow gauge lines were quite sucessful.