The multibillion dollar tunnel extension is dependent on federal funding grants that are not yet signed. Even if the grants are approved by 2025, the earliest the 1.3 miles tunnel extension would be built is 2031, seven years from now. And that's highly optimistic given the slow rate of approvals for new transit projects in san jimsanfrancisco. The new crosstown chinatown streetcar link was well over budget by hundreds of millions of dollars and was delayed about two years in the construction phase