The highly confidential budget review,completed about 18 months ago,shows the biggest projected cost overruns are for new trains and systems;excavating tunnels and sites for underground stations,such as atMartin Place andBarangaroo;and extensive work atCentral andSydenham stations.
While blaming"market pressures"for much of the cost blowout,it found"significant"under estimates in the much-vaunted project's final business case,which was completed about five years ago,for new trains and systems,as well as the scope of works at Chatswood.
The cost of buying new trains and systems,and then integrating them into the rail network,is projected to nearly double to $2.3 billion.
The budget review reveals that nearly $220 million for temporary transport,which includes putting on replacement buses while the existing Bankstown rail line is closed,was"not anticipated"in the project’s final business case five years ago.
The revelations raise questions about how the government will find the money to cover a blowout in the City and Southwest metro line,while committing the state to other rail projects whose cost will run into the tens of billions of dollars this decade.