I'm not surprised that the bidding for a new high speed rail line between Rio de Janeiro and Sao Paulo has been suspended due to lack of interest. Anyone who thinks that you can build a new, electric passenger railway between two major urban areas across rugged and mountainous terrain for less than $80million a kilometre is dreaming¹. In fact, it may cost even more if there are lots of tunnels. The state bank BNDES (the state-owned development bank) suggested a price of about $60million per km.
The Latin American Herald Tribune, reporting the decision to suspend bidding, quotes the President of Brazil as saying, "I don’t believe the staff of the BNDES could have been so mistaken”. Why not, Dear Sir? They were probably acting in good faith, but I suspect they ignored project, political or security risks and didn't count financing costs in the commercial money market. What you might think the actual construction and equipment will cost and what a bidder, in the form of an international consortium, will charge in his price is quite different. In this case, 30% different.
This proposal for a Rio to Sao Paulo high speed rail link has been around for 10 years to my knowledge and it's always been regarded as a high risk project, with the stop-go politics of the region, local and international recessions and the construction and security problems of the area all worrying possible bidders.
If there is a consistent approach, political will at all levels and a commitment from the government to support the project, come what may, then you might get more interest from potential investors and bidders. Without it - no chance.
Footnote 1: The Chinese quote a cost of $25million/km for their Beijing-Shanghai high speed line but they wouldn't include finance and risk. The line was also very long, at 1302 kms, providing substantial economies of scale.