If San Francisco were an hour closer to Davis, how would that change life in Davis? We might find out in the next 10 to 20 years, thanks to a program that is starting to take shape now. Link21, sponsored by BART and the Capitol Corridor, would add a second transbay rail crossing as part of an ambitious, expensive plan to extend rail connections throughout the 21-county megaregion that stretches from Yuba County to Monterey. The program’s components include faster Capitol Corridor train service between Sacramento and San Francisco, among other changes.