I've been playing some of the freight timetables for the new San Bernadino route and I had a AI train routed on to my track on more than one occasion. I know this is the early release but I know that nothing is going to be changed on launch day from what people are playing now so please let me know if you have seen the same thing when you play these activities.
San Bernadino has some manual switches along the line which the driver needs to change to route his train into a passing loop or siding. Unfortunately this does mean that you have to keep checking the map to see if there are any oncoming trains and make sure that either you or the other train is routed into the siding. I'm sure Matt mentioned it on one of the streams and told us that DTG put this feature in because it's true to life and that they didn't want to just put in all automatic switches.