Not practical, but opens a nice discussion point.
At barely 50 mile an LA to San Bernardino high-speed train would be a colossal waste of money on a fast train. The train would hardly get up to top speed and would need to begin slowing down to stop.
Unless a small regional airline line serves the 2 cities, I do not see any direct flights from San Bernardino to San Francisco. So San Bernardino residents going to San Francisco have to drive direct or drive to LA to take a plane.
Now an efficient light rail system from San Bernardino to LA would not only help daily commuters, but it would act as a feeder to a high-speed train running north from LA to San Francisco.
The population density is there to support such a system if properly designed, laid out and operated in a timely manner. Running late all the time, like many transit systems in the US, will not cut it with commuters looking to avoid traffic.
Of course that would be a comprehensive solution to some of Southern Californias traffic and pollution problems. Something I fear is beyond the grasp of many politicians.
