I picked up a DVD recently at an LA train hobby shop, a Pentrex video documenting day to day operations on the SP/NWP around 1992/1994. If you haven't caught this yet, its worth it. I'm about half way through. It had nice shots of the operation of the Napa, Petaluma and Black Point bridges, and yard action in Petaluma. It's amusing to hear the narrator speak about frenzied activity in the Petaluma yard. You really get a sense of the teamwork and organization required to get cargo from one end to the other.
Looks like Pentrex is in the neighborhood of me here in Pasadena.