With California's population projected to grow by 21 million by 2050, rail transportation will be vital to the state's efficient movement of freight and people, a new research report concludes.Titled "Rail and California Economy," the report presents case studies and analysis of freight- and passenger-rail transportation on land use, freeway congestion and the movement of commodities, and those factors' effects on the state's economy.The report was prepared by the University of California-Berkeley and released by the California Department of Transportation (Caltrans).