The only general freight railway opened in Australia this century is the Alice Springs to Darwin railway. The line opened in 2004 and by 2009 had captured ninety percent of the intermodal traffic from the parallel Stuart Highway. Rail rates were ten to twenty percent lower than road with similar transit times.
However the Darwin corridor is unique in its length, alignment and population demand, so it's unlikely any future freight corridor will achieve the same sort of market saturation.
Aurizon and PN are the two largest rail freight companies in Australia, they largely use their own rollingstock or rollingstock owned by customers.
In Queensland, the largest tonnage freight market on the east coast of Australia - with more than 225-million tonnes on rail per annum - there are no parties providing general rollingstock for lease, with all equipment owned by operators or by customers (with the exception of the GATX-owned acid tankers leased by Incitec Pivot).