What is valuable and what we need more of isn't regional trains is light commuter rail. This is the rapid transit system the SF Bay Area could have had today had people had more foresight to approve it back in the 1950s.

http://www.jakecoolidgecartography.com/regional-rapid-transi...

https://www.flickr.com/photos/walkingsf/4080507945/sizes/l/

Imagine the San Francisco Bay Area with a commuter train system comparable to that of NYC and the great NY Metropolitan Area.