To be safe and reliable, HSR needs a secure trackway, totally grade separated. “Blended Rail” (e.g., HSR on Caltrain tracks) would still have many grade crossings. It would be NEITHER SAFE NOR RELIABLE.

In grade crossing accidents, the train usually survives. Not always, though. Google “Bourbonnais Train Accident”. On 79 mph track (like on Caltrain), an Amtrak train struck a heavily-laden truck, derailing two locomotives; 11 of 14 passenger train cars were scattered trackside; 11 passengers were killed and 228 injured. That was an accident, a bit over two years before the terrorism of 9/11/01. HSR – faster than 79 mph – at grade crossings would be highly vulnerable to the demented or the terrorist. Too high a price for a “one-seat ride” into San Francisco!

HSR needs total grade separation. The first Bay Area HSR should truncate at San Jose, with cross-platform transfers there to Caltrain and Capitol Corridor. BART is planned but unfunded to there also, greatly enhancing connectivity.

Future HSR along Amtrak’s East Bay Mulford route and on to Sacramento could have a transfer station at the BART overhead in Oakland, six to ten minutes from BART’s four downtown San Francisco stations, with BART trains about every four minutes.