The California bullet train authority, despite spiraling cost increases, schedule delays and technical snafus over the last five years, told the Legislature on Wednesday it has a solid plan to build an operating segment in the Central Valley that would economically transform the region.

The report contains some sobering caveats that legislators and state leaders will have to consider: It will cost a stunning $20.4 billion to complete just a 171-mile segment between Merced and Bakersfield, a commitment of an additional $15 billion over what has been spent to date for paper studies, environmental reports and construction.

Aiming to improve its internal operation — harshly criticized for years by auditors, analysts and reviewers — the rail authority would reduce its heavy reliance on outside consultants, said Lenny Mendonca, rail authority chairman, in a letter at the front of the report.

The rail authority asserts it has funding to complete the system, though at the low side of revenue estimates, it would end up almost broke by 2028 when the first train shoots through farm country at 220 miles per hour. On the high side of revenue estimates, it would have $3 billion left over — not enough to complete links to either Southern California or the Bay Area.