The California Legislative Analyst's Office's said in a report Tuesday that the funding for the first stage of the state's high-speed system is highly uncertain.
The report said possible sources of funding for the first phase of the California High-Speed Rail Authority's project laid out in the draft business plan are "highly speculative."
And since Congress hasn't approved any funding for high-speed rail next year, the LAO said funding to complete the system may never materialize.
The office also said the authority's economic analysis in the draft plan portrays the project more favorably than warranted.
The report added that the first construction segment of the system would be unusable and thus would not meet one of the requirements for appropriation of bond proceeds.
According to the draft business plan, the authority estimates capital costs could reach $98.5 billion in year-of-expenditure dollars over 30 years to build 500 miles of high-speed passenger train lines between San Francisco and Los Angeles. Last year, the authority said it expected a high-end cost of $45 billion.
State lawmakers created the rail authority in 1996 to plan a high-speed passenger train system to link the Los Angeles and San Francisco Bay regions.
In 2008, voters approved a $9.95 billion general obligation bond measure to seed construction.