Instead of running to Darwin, the Inland Rail would be built from south to north, linking Melbourne to Brisbane.The first official business case, released in 2015, put the cost at $9.9 billion.By 2020, that figure had climbed to $16.4 billion.Within two years of that, internal estimates pushed it beyond $30 billion.Then, days before this year's federal budget, another internal review raised the projected cost to $45 billion, and Infrastructure Minister Catherine King called for construction to be paused north of Parkes.Considering the project has haemorrhaged public money since its inception, Mr Compton conceded it was necessary 'to stop the bleeding.'"But then they then didn't announce anything to fix up what the bleeding had caused," he said.Ms King told 7.30 it was a tough decision to make."It wasn't a decision that I've enjoyed taking either, to be honest," she said."I want to build things I think that shows a lack of understanding about this project and a lack of understanding about how budgets work."But that is exactly what One Nation MP Barnaby Joyce has claimed.During his tenure as Nationals leader and deputy prime minister, Mr Joyce became the project's chief political advocate.He remains a vocal supporter and told 7.30 he doubts the figures."But they can't actually clarify exactly where the blowout is beyond this stupendous number."Ms King defended her office's decision to withhold information from the report because of "commercial in confidence," telling 7.30 "we are working with Inland Rail and my department at the moment to look at what else we can release"."It contains a huge amount of data ..