Building California’s high-speed rail project could cost $98.5 billion over 20 years, more than twice what was previously thought, according to a draft copy of a business plan obtained late Monday by The Bee.  The amount is still far less than the cost of expanding airport and highway systems to accommodate the state’s growing population, the California High-Speed Rail Authority said in the report. Even with conservative ridership and cost estimates, it said, the system will operate at a profit.