Sorry Steve; non of the above.
Only one government is involved, Queensland. There is no corruption; if there was then that state's corruption commission would be involved. The situation comes largely from failures by several people at various stages of the procurement and construction processes.
The tender included provisions which can only be considered onerous. They were copied from a previous tender issued by New South Wales. It is the presence of these provisions which caused the intended supplier to not tender having been badly burned by the NSW experience. Interestingly they are involved in the process of fixing the problems.
A major issue in both cases is the absence of quality control at the place of manufacture; India in the present case and China in the previous case.
It would seem that some lessons are not easily learned. NSW has received first deliveries of driverless trains from India. Testing is underway but commencement in service could be 12 months away. First deliveries of new trains for intercity services is awaited from Korea. These are for services to Newcastle, Lithgow and Kiama. The approach to Lithgow is through 10 tunnels. It has been revealed that the cars ordered are too wide for the tunnels. The public requirement is for reversible seats. The order is for fixed direction seats. The political repercussions are well under way.
The whole matter in both states is what happens when economic theory and political ideology overrule all else.
Although there's no corruption, it seems there has been a huge waste of taxpayer's money, as the cost of rectifying the problems is likely to be substantial (as far as I understand).
On the most basic level, it seems that the procurement process and contracts did not set the correct specifications. In that case surely quality control wouldn't solve this problem, as it would be far to late by that stage.
The manufacturer was not required to meet the disability regulations, so they would not be willing to change the design without significant extra payment.
It seems to me that if no investigation (internal rather than criminal) is carried out, then lessons are unlikely to be learnt.
A rather sad situation.